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Regio- and enantioselective synthesis of acyclic quaternary carbons via organocatalytic addition of organoborates to (Z)-Enediketones. Nat Commun 2024; 15:504. [PMID: 38218961 PMCID: PMC10787796 DOI: 10.1038/s41467-024-44744-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 01/03/2024] [Indexed: 01/15/2024] Open
Abstract
The chemical synthesis of molecules with closely packed atoms having their bond coordination saturated is a challenge to synthetic chemists, especially when three-dimensional control is required. The organocatalyzed asymmetric synthesis of acyclic alkenylated, alkynylated and heteroarylated quaternary carbon stereocenters via 1,4-conjugate addition is here catalyzed by 3,3´-bisperfluorotoluyl-BINOL. The highly useful products (31 examples) are produced in up to 99% yield and 97:3 er using enediketone substrates and potassium trifluoroorganoborate nucleophiles. In addition, mechanistic experiments show that the (Z)-isomer is the reactive form, ketone rotation at the site of bond formation is needed for enantioselectivity, and quaternary carbon formation is favored over tertiary. Density functional theory-based calculations show that reactivity and selectivity depend on a key n→π* donation by the unbound ketone's oxygen lone pair to the boronate-coordinated ketone in a 5-exo-trig cyclic ouroboros transition state. Transformations of the conjugate addition products to key quaternary carbon-bearing synthetic building blocks proceed in good yield.
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2
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Synthesis of Trisubstituted Chromanes by Lewis-Base-Catalyzed Three-Component Electrophilic Thiofunctionalization of Cyclopropene with Phenols via a Formal [3 + 3] Annulation. Org Lett 2022; 24:5693-5697. [PMID: 35921617 DOI: 10.1021/acs.orglett.2c02072] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A Lewis-base-catalyzed three-component electrophilic thiofunctionalization of cyclopropene with phenol is developed to furnish various trisubstituted chromanes in high trans-diasteroselectivity. This metal-free protocol is easy to scale-up, offers a unique 2,2,3-substitution pattern, and delivers chromanes with diversified core substitution patterns. The unprecedented tolerance of strong electron-withdrawing substituents at the phenol renders the protocol indispensable to access the otherwise inaccessible chromane chemical space that is important for medicinal chemistry campaigns.
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3
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Chiral dihydroxytetraphenylene-catalyzed enantioselective conjugate addition of boronic acids to β-enaminones. Org Chem Front 2022. [DOI: 10.1039/d1qo01845k] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
An efficient (S)-2,15-Cl2-DHTP-catalyzed enantioselective conjugate addition of organic boronic acids to β-enaminones has been developed.
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4
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Catalytic Approaches to Multicomponent Reactions: A Critical Review and Perspectives on the Roles of Catalysis. Molecules 2021; 27:132. [PMID: 35011363 PMCID: PMC8746711 DOI: 10.3390/molecules27010132] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 12/20/2021] [Accepted: 12/23/2021] [Indexed: 01/17/2023] Open
Abstract
In this review, we comprehensively describe catalyzed multicomponent reactions (MCRs) and the multiple roles of catalysis combined with key parameters to perform these transformations. Besides improving yields and shortening reaction times, catalysis is vital to achieving greener protocols and to furthering the MCR field of research. Considering that MCRs typically have two or more possible reaction pathways to explain the transformation, catalysis is essential for selecting a reaction route and avoiding byproduct formation. Key parameters, such as temperature, catalyst amounts and reagent quantities, were analyzed. Solvent effects, which are likely the most neglected topic in MCRs, as well as their combined roles with catalysis, are critically discussed. Stereocontrolled MCRs, rarely observed without the presence of a catalytic system, are also presented and discussed in this review. Perspectives on the use of catalytic systems for improved and greener MCRs are finally presented.
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5
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Enantioselective γ-Addition-Driven Cascade of β,γ-Unsaturated Ketones by Ion-Pair Catalysis: Access to Chiral 1,3-Dioxolochroman Scaffolds. Org Lett 2021; 24:38-42. [PMID: 34932357 DOI: 10.1021/acs.orglett.1c03567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A highly enantioselective γ-addition-driven cascade of β,γ-unsaturated carbonyl compounds by bifunctional ion-pair catalysis has been developed. With this protocol, a range of functionalized chiral 1,3-dioxolochroman derivatives were prepared in high yields with superior stereoselectivities (>99% ee and >20:1 dr). The utility of this method was demonstrated by one-pot synthesis, scaled-up preparation, and facile transformation. Moreover, mechanistic investigations provided insights into the reaction pathway and the origin of chiral induction.
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6
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Crown Ether-Derived Chiral BINOL: Enantioselective Michael Addition of Alkenyl Boronic Acids to α,β-Unsaturated Ketones. ACS OMEGA 2021; 6:35093-35103. [PMID: 34963990 PMCID: PMC8697596 DOI: 10.1021/acsomega.1c05875] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 11/08/2021] [Indexed: 06/14/2023]
Abstract
A new class of aza-crown ether-derived chiral BINOL catalysts were designed, synthesized, and applied in the asymmetric Michael addition of alkenylboronic acids to α,β-unsaturated ketones. It was found that introducing aza-crown ethers to the BINOL catalyst could achieve apparently higher enantioselectivity than a similar BINOL catalyst without aza-crown ethers did, although the host-guest complexation of alkali ions by the aza-crown ethers could not further improve the catalysis effectiveness. Under mediation of the aza-crown ether-derived chiral BINOL and in the presence of a magnesium salt, an array of chiral γ,δ-unsaturated ketones were furnished in good enantioselectivities (81-95% ees).
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7
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Organocatalyzed Enantioselective Conjugate Addition of Boronic Acids to β,γ-Unsaturated α-Ketoesters. J Org Chem 2021; 86:18211-18223. [PMID: 34818889 DOI: 10.1021/acs.joc.1c02497] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We report herein the (R)-3,3'-Br2-BINOL-catalyzed enantioselective conjugate addition of organic boronic acids to β,γ-unsaturated α-ketoesters to generate the corresponding Michael addition products in moderate to high yields and with moderate to excellent enantioselectivities (up to 99% ee). This catalytic system features characteristics of mild reaction conditions, high efficiency, and tolerance to alkenylboronic acids and heteroarylboronic acids.
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8
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Recent Advancement in the One-Pot Synthesis of the Tri-Substituted Methanes (TRSMs) and Their Biological Applications. Curr Org Synth 2021; 19:86-114. [PMID: 34515005 DOI: 10.2174/1570179418666210910105342] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/08/2021] [Accepted: 07/19/2021] [Indexed: 11/22/2022]
Abstract
The history of tri-substituted methanes (TRSMs) in chemical industries is much older. Tri-substituted methanes were previously used as dyes in the chemical industries. Still, there is a significant surge in researchers' interest in them due to their wide range of bioactivities. Tri-substituted methane derivatives show a wide range of biological activities like anti-tumor, antimicrobial, antibiofilm, antioxidant, anti-inflammatory, anti-arthritic activities. Due to the wide range of medicinal applications shown by tri-substituted methanes, most of the methodologies reported in the literature for the synthesis of TRSMs are focused on the one-pot method. This review explored the recently reported one-pot processes for synthesizing tri-substituted methanes and their various medicinal applications. Based on the substitution attached to the -CH carbon, this review categorizes them into two major classes: (I) symmetrical and (II) unsymmetrical trisubstituted methanes. In addition, this review gives an insight into the growing opportunities for the construction of trisubstituted scaffolds via one-pot methodologies. To the best of our knowledge, no one has yet reported a review on the one-pot synthesis of TRSMs. Therefore, here we present a brief literature review of the synthesis of both symmetrical and unsymmetrical TRSMs covering various one-pot methodologies along with their medicinal applications.
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Total Synthesis of (-)-Canadine, (-)-Rotundine, (-)-Sinactine, and (-)-Xylopinine Using a Last-Step Enantioselective Ir-Catalyzed Hydrogenation. J Org Chem 2021; 86:8143-8153. [PMID: 34076443 DOI: 10.1021/acs.joc.1c00602] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A concise asymmetric total synthesis of a group of tetrahydroprotoberberine alkaloids, (-)-canadine, (-)-rotundine, (-)-sinactine, and (-)-xylopinine, has been accomplished in three steps from the commercially available corresponding disubstituted phenylethylamine and disubstituted benzaldehyde. Our synthesis toward these four alkaloids took advantage of the following strategy: in the first step, we achieved an efficient and sustainable synthesis of secondary amine hydrochlorides via a fully continuous flow; in the second step, we developed a Pictet-Spengler reaction/Friedel-Crafts hydroxyalkylation/dehydration cascade for the construction of the dihydroprotoberberine core structure (ABCD-ring); and in the last step, Ir-catalyzed enantioselective hydrogenation was employed for the introduction of the desired stereochemistry at the C-14 position in the tetrahydroprotoberberine alkaloids. This work significantly expedites the asymmetric synthesis of the entire tetrahydroprotoberberine alkaloid family as well as a more diverse set of structurally related non-natural analogues.
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Chiral Selenide-Catalyzed, Highly Regio- and Enantioselective Intermolecular Thioarylation of Alkenes with Phenols. ACS Catal 2021. [DOI: 10.1021/acscatal.1c00296] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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11
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Dearomatization‐Rearomatization Strategy for
ortho
‐Selective Alkylation of Phenols with Primary Alcohols. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202010845] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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12
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Dearomatization‐Rearomatization Strategy for
ortho
‐Selective Alkylation of Phenols with Primary Alcohols. Angew Chem Int Ed Engl 2020; 60:4043-4048. [PMID: 33166067 DOI: 10.1002/anie.202010845] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/30/2020] [Indexed: 12/28/2022]
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13
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Phosphoric Acid Catalyzed Formation of Hydrogen-Bonded o-Quinone Methides. Enantioselective Cycloaddition with β-Dicarbonyl Compounds toward Benzannulated Oxygen Heterocycles. J Org Chem 2020; 85:11699-11720. [DOI: 10.1021/acs.joc.0c01375] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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14
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Diastereo- and Enantioselective Construction of Biologically Important Chiral 1,3-Dioxolochroman Frameworks via Catalytic Asymmetric [4+2] Cycloaddition. J Org Chem 2020; 85:5403-5415. [PMID: 32212612 DOI: 10.1021/acs.joc.0c00119] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A diastereo- and enantioselective construction of biologically important chiral 1,3-dioxolochroman frameworks has been established via chiral phosphoric acid (CPA)-catalyzed asymmetric [4+2] cycloaddition of ortho-quinone methides with 3-methyl-2-vinylindoles. By using this approach, a series of indole-based chiral 1,3-dioxolochromans were synthesized with structural diversity in generally good yields, excellent diastereoselectivities and high enantioselectivities (up to 98% yields, >95:5 dr, 97% ee). The evaluation on the cytotoxic activity of some selected products indicated that this class of chiral 1,3-dioxolochroman derivatives had some extent of anti-cancer activity. This reaction not only provides an efficient synthetic method for accessing chiral 1,3-dioxolochroman derivatives with structural diversity and optical purity but also will enrich the research contents of catalytic asymmetric [4+2] cycloadditions involving ortho-quinone methides. In addition, the bioassay of these compounds will cast a light on discovering useful bioactivities of chiral 1,3-dioxolochroman derivatives, which will be helpful for finding lead compounds.
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15
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Asymmetric Catalytic [4+5] Annulation of
ortho
‐Quinone Methides with Vinylethylene Carbonates and its Extension to Stereoselective Tandem Rearrangement. Chemistry 2020; 26:3803-3809. [DOI: 10.1002/chem.201904903] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Indexed: 12/21/2022]
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16
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Hydride transfer enabled switchable dearomatization of indoles in the carbocyclic ring and the pyrrole ring. Org Chem Front 2020. [DOI: 10.1039/d0qo00658k] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hydride transfer enabled the first success of the regioselective dearomatization of indoles in the carbocyclic ring and the pyrrole ring, which was induced by ortho-quinone methides and vinylogous iminium intermediates, respectively.
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Enantioselective Synthesis of Triarylmethanes
via
Organocatalytic 1,6‐Addition of Arylboronic Acids to
para
‐Quinone Methides. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201801446] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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18
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Abstract
Anhydrous FeCl3 in the presence of 2,6-lutidine promotes the substrate-controlled enantioselective [4 + 2]-cycloaddition and crotylation reaction between an enantioenriched ( S, E)-crotyl silane and in situ generated ortho-quinone methides ( oQMs). The reaction produces both the chiral chroman and crotylation products in a ratio reflective of the electronic nature of the parent oQM with overall combined yields up to 96%. A ring-opening and elimination sequence was subsequently developed to provide direct access to the crotylation products, containing two contiguous tertiary carbon stereocenters, in good yields and enantioselectivities.
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20
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Chiral Diol-Based Organocatalysts in Enantioselective Reactions. Molecules 2018; 23:molecules23092317. [PMID: 30208621 PMCID: PMC6225256 DOI: 10.3390/molecules23092317] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 09/03/2018] [Accepted: 09/06/2018] [Indexed: 12/22/2022] Open
Abstract
Organocatalysis has emerged as a powerful synthetic tool in organic chemistry in the last few decades. Among various classes of organocatalysis, chiral diol-based scaffolds, such as BINOLs, VANOLs, and tartaric acid derivatives, have been widely used to induce enantioselectivity due to the ability of the hydroxyls to coordinate with the Lewis acidic sites of reagents or substrates and create a chiral environment for the transformation. In this review, we will discuss the applications of these diol-based catalysts in different types of reactions, including the scopes of reactions and the modes of catalyst activation. In general, the axially chiral aryl diol BINOL and VANOL derivatives serve as the most competent catalyst for most examples, but examples of exclusive success using other scaffolds, herein, suggests that they should not be overlooked. Lastly, the examples, to date, are mainly from tartrate and biaryl diol catalysts, suggesting that innovation may be available from new diol scaffolds.
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Activation of Boron Compounds by O-Monoacyltartaric Acid Catalysts. J SYN ORG CHEM JPN 2018. [DOI: 10.5059/yukigoseikyokaishi.76.596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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22
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A Dienyl Boronate-Aryl Nitroso Ene Reaction Entry toC-Pyrrolyl Nitrones and Subsequent Conversion to Isoxazolidines. ChemistrySelect 2018. [DOI: 10.1002/slct.201800945] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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23
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Overview on the Recent Strategies for the Enantioselective Synthesis of 1, 1-Diarylalkanes, Triarylmethanes and Related Molecules Containing the Diarylmethine Stereocenter. ChemCatChem 2018. [DOI: 10.1002/cctc.201701601] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Forty Years after “Heterodiene Syntheses with α,β-Unsaturated Carbonyl Compounds”: Enantioselective Syntheses of 3,4-Dihydropyran Derivatives. Chem Rev 2018; 118:2080-2248. [DOI: 10.1021/acs.chemrev.7b00322] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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25
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Boronic acid/Brønsted acid co-catalyst systems for the synthesis of 2H-chromenes from phenols and α,β-unsaturated carbonyls. Org Biomol Chem 2018; 14:6703-11. [PMID: 27314604 DOI: 10.1039/c6ob01026a] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Protocols for the synthesis of substituted 2H-chromenes from α,β-unsaturated carbonyls and phenols are described. Optimal combinations of arylboronic acids and Brønsted acids have been identified, such that both can be employed in catalytic quantities to accelerate these condensations. The method has been used to synthesize a variety of substituted 2H-chromenes, as well as photochromic naphthopyrans. The use of pentafluorophenylboronic acid and diphenylphosphinic acid enabled an expansion of the electrophile scope to include α,β-unsaturated ketones. Hall's 'phase-switching' of boronic acids has been exploited to achieve the separation of the two co-catalysts from unpurified reaction mixtures by a simple liquid-liquid extraction.
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Abstract
Iron(III) salts promote the condensation of aldehydes or acetals with electron-rich phenols to generate ortho-quinone methides that undergo Diels-Alder condensations with alkenes. The reaction sequence occurs in a single vessel to afford benzopyrans in up to 95% yield. The reaction was discovered while investigating a two-component strategy using 2-(hydroxy(phenyl)methyl)phenols to access the desired ortho-quinone methide in a Diels-Alder condensation. The two-component condensation also afforded the corresponding benzopyran products in yields up to 97%. Taken together, the two- and three-component strategies using ortho-quinone methide intermediates provide efficient access to benzopyrans in good yields and selectivities.
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Asymmetric Petasis Borono-Mannich Allylation Reactions Catalyzed by Chiral Biphenols. Angew Chem Int Ed Engl 2017; 56:1544-1548. [PMID: 28052567 PMCID: PMC5716625 DOI: 10.1002/anie.201611332] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Indexed: 12/25/2022]
Abstract
Chiral biphenols catalyze the asymmetric Petasis borono-Mannich allylation of aldehydes and amines through the use of a bench-stable allyldioxaborolane. The reaction proceeds via a two-step, one-pot process and requires 2-8 mole % of 3,3'-Ph2 -BINOL as the optimal catalyst. Under microwave heating the reaction affords chiral homoallylic amines in excellent yields (up to 99 %) and high enantioselectivies (er up to 99:1). The catalytic reaction is a true multicomponent condensation reaction whereas both the aldehyde and the amine can possess a wide range of structural and electronic properties. Use of crotyldioxaborolane in the reaction results in stereodivergent products with anti- and syn-diastereomers both in good diastereoselectivities and enantioselectivities from the corresponding E- and Z-borolane stereoisomers.
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28
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Asymmetric Petasis Borono-Mannich Allylation Reactions Catalyzed by Chiral Biphenols. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201611332] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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29
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Multicomponent reaction through cooperative trio catalysis incorporating enamine, Brønsted acid and metal Lewis acid catalysis: a concise route to access chromans. Org Biomol Chem 2017; 15:4933-4936. [DOI: 10.1039/c7ob00753a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Chroman formation is achieved through a tricatalytic system incorporating enamine, metal Lewis acid and Brønsted acid catalysis.
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Abstract
Herein is reported the direct asymmetric addition of phenol nucleophiles to benzopyrylium salts as a means to produce enantioenriched flavonoid-like compounds. This enantioselective C-C bond construction was achieved through a chiral anion phase-transfer strategy that mimics the proposed biosynthesis of this structurally diverse set of natural products. The utility of this methodology was demonstrated in enantioselective synthesis of a 2,8-dioxabicyclo[3.3.1]nonane and a 2,4-diarylbenzopyran.
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