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Weitkamp RF, Neumann B, Stammler H, Hoge B. Phosphorus-Containing Superbases: Recent Progress in the Chemistry of Electron-Abundant Phosphines and Phosphazenes. Chemistry 2021; 27:10807-10825. [PMID: 34032319 PMCID: PMC8362139 DOI: 10.1002/chem.202101065] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Indexed: 01/11/2023]
Abstract
The renaissance of Brønsted superbases is primarily based on their pronounced capacity for a large variety of chemical transformations under mild reaction conditions. Four major set screws are available for the selective tuning of the basicity: the nature of the basic center (N, P, …), the degree of electron donation by substituents to the central atom, the possibility of charge delocalization, and the energy gain by hydrogen bonding. Within the past decades, a plethora of neutral electron-rich phosphine and phosphazene bases have appeared in the literature. Their outstanding properties and advantages over inorganic or charged bases have now made them indispensable as auxiliary bases in deprotonation processes. Herein, an update of the chemistry of basic phosphines and phosphazenes is given. In addition, due to widespread interest, their use in catalysis or as ligands in coordination chemistry is highlighted.
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Affiliation(s)
- Robin F. Weitkamp
- Centrum für Molekulare MaterialienFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Beate Neumann
- Centrum für Molekulare MaterialienFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Hans‐Georg Stammler
- Centrum für Molekulare MaterialienFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
| | - Berthold Hoge
- Centrum für Molekulare MaterialienFakultät für ChemieUniversität BielefeldUniversitätsstraße 2533615BielefeldGermany
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Britvin SN, Rumyantsev AM, Zobnina AE, Padkina MV. Between Adamantane and Atrane: Intrabridgehead Interactions in the Cage-Like Phosphane Related to a Novel Tris(homoadamantane) Ring System. Chemistry 2016; 22:14227-35. [PMID: 27531034 DOI: 10.1002/chem.201601637] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Indexed: 11/05/2022]
Affiliation(s)
- Sergey N. Britvin
- Department of Crystallography; Saint Petersburg State University; Universitetskaya Nab. 7/9 199034 St. Petersburg Russia
| | - Andrey M. Rumyantsev
- Department of Genetics and Biotechnology; Saint Petersburg State University; Universitetskaya Nab. 7/9 199034 St. Petersburg Russia
| | - Anastasia E. Zobnina
- Department of Genetics and Biotechnology; Saint Petersburg State University; Universitetskaya Nab. 7/9 199034 St. Petersburg Russia
| | - Marina V. Padkina
- Department of Genetics and Biotechnology; Saint Petersburg State University; Universitetskaya Nab. 7/9 199034 St. Petersburg Russia
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Gibb JN, Goodman JM. The formation of high-purity isocyanurate through proazaphosphatrane-catalysed isocyanate cyclo-trimerisation: computational insights. Org Biomol Chem 2013; 11:90-7. [PMID: 23172305 DOI: 10.1039/c2ob26547h] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Polyurethane foams are widely used materials and control of their physical properties is a significant challenge. Management of cyclo-trimerisation during the polymerisation process is vital when tailoring the mechanical properties of the foam. Proazaphosphatranes are known to efficiently catalyse the cyclo-trimerisation of organic isocyanates, giving high purity isocyanurate with little uretdione by-product. The mechanism of this catalysis was previously unknown, although some zwitterionic intermediates have been identified spectroscopically. We have investigated a nucleophilic-catalysis reaction pathway involving sequential addition of methyl isocyanate to activated zwitterionic intermediates using density functional theory calculations. Evidence for significant transannulation by the proazaphosphatrane nitrogen was found for all intermediates, offering stabilisation of the phosphonium cation. Steric crowding at the proazaphosphatrane nucleophilic phosphorus gives rise to a preference for direct isocyanurate formation rather than via the uretdione, in sharp contrast to the uncatalysed system which has been found to preferentially proceed via the kinetic uretdione product. The investigations suggest the mechanism of proazaphosphatrane catalysed cyclo-oligomerisation does not proceed via the uretdione product, and hence why little of this impurity is observed experimentally.
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Affiliation(s)
- Jack N Gibb
- Unilever Centre For Molecular Science Informatics, Department of Chemistry, Lensfield Road, Cambridge CB2 1EW, UK
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Lee J, Kim Y. 2,8,9-Tris(2-methyl-prop-yl)-2,5,8,9-tetra-aza-1λ(5)-phosphatricyclo-[3.3.3.0(1,5)]undecan-5-ium chloride dihydrate. Acta Crystallogr Sect E Struct Rep Online 2012; 68:o3317. [PMID: 23476161 PMCID: PMC3588925 DOI: 10.1107/s1600536812045618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Accepted: 11/05/2012] [Indexed: 06/01/2023]
Abstract
The asymmetric unit of the title hydrated salt, C18H40N4P(+)·Cl(-)·2H2O, consists of two ionic mol-ecules and four water mol-ecules. The mol-ecular geometry around the penta-coordinate P atom is trigonal-bipyramidal, with a H atom and an apical N atom in axial positions and three N atoms with isobutyl substituents in equatorial positions. The Cl(-) ions and water mol-ecules are connected via O-H⋯Cl hydrogen bonds, forming chains along [100]. The ethyl-ene bridging groups are disordered with refined site-occupancy ratios of 0.578 (9):0.422 (9).
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Affiliation(s)
- Junseong Lee
- Department of Chemistry, Chonnam National University, Gwangju 500-757, Republic of Korea
| | - Youngjo Kim
- Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk 361-763, Republic of Korea
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Kisanga P, Mcleod D, Liu X, Yu Z, Ilankumaran P, Wang Z, Mclaughlin PA, Verkade JG. New Chemistry of ZP(RNCH2CH2)3N Systems. PHOSPHORUS SULFUR 2008. [DOI: 10.1080/10426509908546192] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Philip Kisanga
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011
- e Department of Chemistry , Iowa State University , Ames, Iowa 50011
| | - Dale Mcleod
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011
- e Department of Chemistry , Iowa State University , Ames, Iowa 50011
| | - Xiaodong Liu
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011
- e Department of Chemistry , Iowa State University , Ames, Iowa 50011
| | - Zhengkun Yu
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011
- e Department of Chemistry , Iowa State University , Ames, Iowa 50011
| | - Palinichamy Ilankumaran
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011
- e Department of Chemistry , Iowa State University , Ames, Iowa 50011
| | - Zhigang Wang
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011
- e Department of Chemistry , Iowa State University , Ames, Iowa 50011
| | - Patrick A. Mclaughlin
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011
- e Department of Chemistry , Iowa State University , Ames, Iowa 50011
| | - John G. Verkade
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011
- e Department of Chemistry , Iowa State University , Ames, Iowa 50011
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Anantharaman G, Elango K. Synthesis of Imidazolium/Benzimidazolium Salts and the Preparation of Silver(I) Complex of Bis‐Benzimidazolium Dibromide. ACTA ACUST UNITED AC 2007. [DOI: 10.1080/15533170701674959] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
| | - Kandasamy Elango
- a Department of Chemistry , Indian Institute of Technology , Kanpur, India
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Affiliation(s)
- Bosco A. D'sa
- a Department of Chemistry , Iowa State University , Ames, Iowa, 50011
| | - John G. Verkade
- a Department of Chemistry , Iowa State University , Ames, Iowa, 50011
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Kárpáti T, Veszprémi T, Thirupathi N, Liu X, Wang Z, Ellern A, Nyulászi L, Verkade JG. Synthesis and Photoelectron Spectroscopic Studies of N(CH2CH2NMe)3PE (E = O, S, NH, CH2). J Am Chem Soc 2006; 128:1500-12. [PMID: 16448120 DOI: 10.1021/ja0547533] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The synthesis and the crystal and molecular structure of N(CH(2)CH(2)NMe)(3)P=CH(2) is reported. The P-N(ax) distance is rather long in N(CH(2)CH(2)NMe)(3)P=CH(2). The ylide N(CH(2)CH(2)NMe)(3)P=CH(2) proved to be a stronger proton acceptor than proazaphosphatrane N(CH(2)CH(2)NMe)(3)P, since it was shown to deprotonate N(CH(2)CH(2)NMe)(3)PH(+). The extremely strong basicity of the ylide is in accordance with its low ionization energy (6.3 eV), which is the lowest in the presently investigated series N(CH(2)CH(2)NMe)(3)P=E (E: CH(2), NH, lone pair, O and S), and to the best of our knowledge it is the smallest value observed for a non-conjugated phosphorus ylide. Computations reveal the existence of two bond strech isomers, and the stabilization of the phosphorus centered cation by electron donation from the equatorial and the axial nitrogens. Similar stabilizing effects operate in the case of protonation of E. A fine balance of these different interactions determines the P-N(ax) distance, which is thus very sensitive to the level of the theory applied. According to the quantum mechanical calculations, methyl substitution at the equatorial nitrogens flattens the pyramidality of this atom, increasing its electron donor capability. As a consequence, the PN(ax) distance in the short-transannular bonded protonated systems and the radical cations is longer by about 0.5 A in the N(eq)(Me) than in the N(eq)(H) systems. Accordingly, isodesmic reaction energies show that a stabilization of about 25 and 10 kcal/mol is attributable to the formation of the transannular bond in case of N(eq)(H) and the experimentally realizable N(eq)(Me) species, respectively.
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Affiliation(s)
- Tamás Kárpáti
- Department of Inorganic Chemistry, Budapest University of Technology and Economics, H-1521 Budapest, Hungary
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Liu X, Thirupathi N, Guzei IA, Verkade JG. An investigation of Staudinger reactions involving cis-1,3,5-triazidocyclohexane and tri(alkylamino)phosphines. Inorg Chem 2004; 43:7431-40. [PMID: 15530094 DOI: 10.1021/ic0492845] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The reaction of 1,3,5-cis-triazidocyclohexane with the electron-rich tris(dialkylamino)phosphines P(NMe(2))(3) (1) and N(CH(2)CH(2)NMe)(3)P (2b) in acetonitrile for 3 h furnished the corresponding tris-phosphazides 1,3,5-cis-(R(3)PN(3))(3)C(6)H(9), 3a (R(3)P = 1) and 3b (R(3)P = 2b), in 90% and 92% yields, respectively. The same reaction with the relatively electron-poor tris(dialkylamino)phosphine MeC(CH(2)NMe)(3)P (4) for 2 days gave the tris-iminophosphorane, 1,3,5-cis-(R(3)PN)(3)C(6)H(9), 5a (R(3)P = 4), in 60% yield. Compound 3b is a thermally stable solid that did not lose dinitrogen when refluxed in toluene for 24 h or when heated as a neat sample at 100 degrees C /0.5 Torr for 10 h. By contrast, tris-phosphazide 3a decomposed to the tris-iminophosphorane 1,3,5-cis-(R(3)PN)(3)C(6)H(9), 5b (R(3)P = 1), in 3 h in quantitative yield upon heating to 100 degrees C in toluene. Factors influencing the formation of the phosphazides or the iminophosphoranes in these reactions are discussed. The reaction of 3b with 4 equiv of benzoic acid gave [N(CH(2)CH(2)NMe)(3)P=NH(2)]PhCO(2) ([6bH]PhCO(2)) in quantitative yield along with benzene (56% yield) and dinitrogen. The same reaction with 3a gave [(Me(2)N)(3)P=NH(2)]PhCO(2) ([7aH]PhCO(2)) (quantitative yield), benzene (15% yield), and dinitrogen(.) Treatment of [6bH]PhCO(2) with KO(t)Bu afforded N(CH(2)CH(2)NMe)(3)P=NH (6b) in 40% overall yield. Compound 6b upon treatment with PhCH(2)CH(2)Br produced [6bH]Br in 90% yield along with styrene. The new compounds were characterized by analytical and spectroscopic methods, and selected compounds (3b, 5a, and [6bH]Br) were structured by X-ray crystallography. A special feature of 3b is its capability to function as a starting material for 6b, which was not accessible by other synthetic routes.
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Affiliation(s)
- Xiaodong Liu
- Departments of Chemistry, Iowa State University, Ames, IA 50011-3111, USA
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Galasso V. Theoretical Study of the Structure and Bonding in Phosphatrane Molecules. J Phys Chem A 2004. [DOI: 10.1021/jp031324n] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- V. Galasso
- Dipartimento di Scienze Chimiche, Università di Trieste, I-34127 Trieste, Italy
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Verkade JG, Kisanga PB. Proazaphosphatranes: a synthesis methodology trip from their discovery to vitamin A. Tetrahedron 2003. [DOI: 10.1016/s0040-4020(03)01204-3] [Citation(s) in RCA: 131] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Wróblewski AE, Verkade JG. P(CH(3)NCH(2)CH(2))(3)N as a dehydrobromination reagent: synthesis of vitamin A derivatives revisited. J Org Chem 2002; 67:420-5. [PMID: 11798312 DOI: 10.1021/jo010648+] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although P(CH(3)NCH(2)CH(2))(3)N (1) was found to be less effective than 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) or 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in the removal of hydrogen bromide from vitamin A intermediates 13-cis-10-bromo-9,10-dihydroretinyl acetates (6) and 14-bromo-9,14-dihydroretinyl acetate (11) when the reaction was carried out in refluxing benzene, in acetonitrile at room temperature it was superior to DBN and DBU. A (31)P NMR study of this reaction suggests that the carbanion generated from acetonitrile-d(3) in the presence of 1 is the basic species that initiates the elimination step. Diastereoselectivity of the nucleophilic addition of (Z)-HC triple bond C(CH(3))=CHCH(2)OH to the carbonyl group of (E)-2-methyl-4-(2',6',6'-trimethyl-1'-cyclohexen-1'-yl)-3-butenal (2) was only moderate (20%), and (9R,10S)-13-cis-11,12-didehydro-9,10-dihydro-10-hydroxyretinol (3b) predominated. The LiAlH(4) reduction of the C triple bond C bond in the diastereoisomeric diols 3 afforded 13-cis-9,10-dihydro-10-hydroxyretinols 4a and 4b as major products together with 11-cis-13-cis-isomers and the deoxygenated compound (3EZ,5EZ,8E)-3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexen-1-yl)-1,3,5,8-nonatetraene (9). Reaction of 15-acetates of the pure diastereoisomeric allylic alcohols 4a and 4b with PBr(3) occurred with significant but not identical retention of configuration, and with concomitant formation of the rearranged bromide 11.
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Wang Z, Zhang G, Guzei I, Verkade JG. PhCHP(MeNCH2CH2)3N: A Novel Ylide for Quantitative E Selectivity in the Wittig Reaction. J Org Chem 2001; 66:3521-4. [PMID: 11348139 DOI: 10.1021/jo0100704] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PhCH=P[MeNCH(2)CH(2)](3)N (1), a semi-stabilized ylide prepared from the commercially available nonionic base P[MeNCH(2)CH(2)](3)N, reacts with aldehydes to give alkenes in high yield with quantitative E selectivity. In contrast with other ylides, this E selectivity is maintained despite changes in the metal ion of the ionic base used to deprotonate 1, temperature, and solvent polarity. In conjunction with structural parameters gained from the X-ray molecular structure of 1, the pathway to E selectivity in these reactions is rationalized by the Vedejs model of Wittig reaction stereochemistry.
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Affiliation(s)
- Z Wang
- Department of Chemistry, Iowa State University, Ames, IA 50011-3111, USA
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P(MeNCH2CH2)3N: a highly selective reagent for synthesizing trans-epoxides from aryl aldehydes. J Org Chem 2000; 65:4560-4. [PMID: 10959859 DOI: 10.1021/jo000122+] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In contrast to its acyclic analogue P(NMe2)3 (1), which in benzene at room temperature reacts with two aryl aldehyde molecules bearing electron-withdrawing groups to give the corresponding diaryl epoxide as an isomeric mixture (trans/cis ratios: 72/28-51/49), P(MeNCH2CH2)3N (2a) under the same reaction conditions is found to be a highly selective reagent that provides epoxides with trans/cis ratios as high as 99/1. These reactions are faster with 2a, because its phosphorus atom is apparently more nucleophilic than that in 1. Thus, it is found that 2a more easily forms 1:1 and 1:2 adducts with one or two molecules of aldehyde, respectively. These adducts apparently are intermediates in the formation of the product epoxide and the corresponding phosphine oxides of 1 and 2a.
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P(MeNCH2CH2)3N: an efficient catalyst for the desilylation of tert-butyldimethylsilyl ethers. J Org Chem 2000; 65:2065-8. [PMID: 10774026 DOI: 10.1021/jo991591i] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
tert-Butyldimethylsilyl (TBDMS) ethers of primary, secondary, and tertiary alcohols and phenolic TBDMS ethers are desilylated to their corresponding alcohols and phenols, respectively, in DMSO, at 80 degrees C, in 68-94% yield in the presence of 0.2-0.4 equiv of P(MeNCH2CH2)3N. Using P(i-PrNCH2-CH2)3N as the catalyst, 85-97% yields of desilylated alcohols were obtained from TBDMS ethers of 1-octanol, 2-phenoxyethanol, and racemic alpha-phenyl ethanol. These are the first examples of desilylations of silyl ethers catalyzed by nonionic bases. Both catalysts were much less effective for the desilylation of tert-butyldiphenylsilyl (TBDPS) ethers (22-45% yield) under the same conditions as used for TBDMS ethers. Possible pathways involving nucleophilic attack of the anion of the solvent molecule (generated by the catalyst) at the Si-O bond of silyl ether or a prior activation of the silyl ether by the catalyst via a P-Si interaction followed by nucleophilic attack of the solvent anion are proposed on the basis of 1H and 31P NMR experimental data.
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Liu X, Ilankumaran P, Guzei IA, Verkade JG. P[(S,S,S)-PhHMeCNCH2CH2]3N: A New Chiral 31P and 1H NMR Spectroscopic Reagent for the Direct Determination of ee Values of Chiral Azides. J Org Chem 2000. [DOI: 10.1021/jo991304a] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Xiaodong Liu
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | | | - Ilia A. Guzei
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - John G. Verkade
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
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Wang Z, Kisanga P, Verkade JG. P(i-PrNCH2CH2)3N: An Effective Lewis Base Promoter for the Allylation of Aromatic Aldehydes with Allyltrimethylsilane. J Org Chem 1999. [DOI: 10.1021/jo990225w] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhigang Wang
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111
| | - Philip Kisanga
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111
| | - John G. Verkade
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111
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Liu X, Verkade JG. Free and Polymer-Bound Tricyclic Azaphosphatranes HP(RNCH(2)CH(2))(3)N(+): Procatalysts in Dehydrohalogenations and Debrominations with NaH. J Org Chem 1999; 64:4840-4843. [PMID: 11674559 DOI: 10.1021/jo990217f] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The commercially available nonionic base P(CH(3)NCH(2)CH(2))(3)N (1a) was shown earlier to be superior to DBU as a stoichiometric reagent for the conversion of primary and secondary alkyl halides to alkenes (Arumugam, S.; Verkade, J. G. J. Org. Chem. 1997, 62, 4827). The precursor cation HP(CH(3)NCH(2)CH(2))(3)N(+) (2) to 1a, which is more stable and less expensive, is reported herein to be an efficient procatalyst for these reactions and also for the debromination of vicinal dibromides using NaH as a relatively inexpensive stoichiometric hydride source in CH(3)CN at room temperature. In dehydrohalogenations requiring more than ca. 10 h, the CH(2)CN(-) ion also acts as a base. By itself, NaH does not function well or at all under the same conditions. A catalytic cycle is proposed in which hydride deprotonates cation 2 liberating catalytic 1a. The cations HP(HNCH(2)CH(2))(3)N(+) (3) and HP[N(polymer)CH(2)CH(2)]N(CH(2)CH(2)NH)(2)(+) (4) are also shown to function as procatalysts for the efficient dehydrohalogenation of RX and for the debromination of vicinal dibromides. The preparation of the heterogeneous procatalyst 4(OTf) is also described.
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Affiliation(s)
- Xiaodong Liu
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
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Synthesis and structural features of new sterically hindered azaphosphatrane systems: ZP(RNCH2CH2)3N. J Organomet Chem 1999. [DOI: 10.1016/s0022-328x(98)01180-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Goumri-Magnet S, Guerret O, Gornitzka H, Cazaux JB, Bigg D, Palacios F, Bertrand G. Free and Supported Phosphorus Ylides as Strong Neutral Brønsted Bases. J Org Chem 1999; 64:3741-3744. [PMID: 11674508 DOI: 10.1021/jo9822030] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stéphanie Goumri-Magnet
- Laboratoire de Chimie de Coordination, 205 route de Narbonne, 31077 Toulouse Cedex, France, Expansia S. A., route d'Avignon, BP 6, 30390 Aramon Cedex, France, Institut Henri Beaufour, 17, avenue Henri descartes, 92350 Le Plessis Robinson, France, and Facultad de Farmacia, Universidad del Pais Vasco, Aparrado 450, 01080 Vitoria, Spain
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McLaughlin PA, Verkade JG. Fluoride-Catalyzed Reduction of Palladium(II) to Palladium(0)−Phosphine Complexes. Organometallics 1998. [DOI: 10.1021/om980490s] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | - John G. Verkade
- Department of Chemistry, Iowa State University, Ames, Iowa 50011-3111
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Affiliation(s)
- Xiao-Dong Liu
- Contribution from Gilman Hall, Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - John G. Verkade
- Contribution from Gilman Hall, Department of Chemistry, Iowa State University, Ames, Iowa 50011
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26
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D'Sa BA, Kisanga P, Verkade JG. Direct Synthesis of α,β-Unsaturated Nitriles Catalyzed by Nonionic Superbases. J Org Chem 1998. [DOI: 10.1021/jo972343u] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Bosco A. D'Sa
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - Philip Kisanga
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
| | - John G. Verkade
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
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Arumugam S, Verkade JG. P(CH3NCH2CH2)3N: A Nonionic Superbase for Efficient Dehydrohalogenation. J Org Chem 1997. [DOI: 10.1021/jo962310z] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - John G. Verkade
- Department of Chemistry, Iowa State University, Ames, Iowa 50011
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28
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D'Sa B, Kisanga P, Mcleod D, Verkade J. P(RNCH 2CH 2) 3N: Superbasic and Catalytic Cages. PHOSPHORUS SULFUR 1997. [DOI: 10.1080/10426509708545627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Bosco D'Sa
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
| | - Philip Kisanga
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
| | - Dale Mcleod
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
| | - John Verkade
- a Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- b Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- c Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
- d Department of Chemistry , Iowa State University , Ames, Iowa 50011, USA
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