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Suzuki K, Sugihara N, Nishimoto Y, Yasuda M. anti-Selective Borylstannylation of Alkynes with (o-Phenylenediaminato)borylstannanes by a Radical Mechanism. Angew Chem Int Ed Engl 2022; 61:e202201883. [PMID: 35485137 DOI: 10.1002/anie.202201883] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Indexed: 12/20/2022]
Abstract
We have achieved the first anti-borylstannylation of alkynes by using (o-phenylenediaminato)borylstannanes. This reaction afforded 1-boryl-2-stannylalkenes with excellent regio- and stereoselectivity by a radical mechanism. This anti-addition manner is in sharp contrast to the syn-selectivity obtained during transition metal-catalyzed borylstannylation. The mild radical conditions enabled a broad substrate scope, and various types of aromatic and aliphatic alkynes were applicable. The origin of regio- and stereoselectivity was elucidated by DFT calculation of the reaction mechanism. The application of the borylstannylation products to cross- or homocoupling reactions provided ready access to either triarylethenes or bisborylbutadienes.
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Affiliation(s)
- Kensuke Suzuki
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Naoki Sugihara
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoshihiro Nishimoto
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Makoto Yasuda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
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Suzuki K, Sugihara N, Nishimoto Y, Yasuda M. anti‐Selective Borylstannylation of Alkynes with (o‐Phenylenediaminato)borylstannanes by a Radical Mechanism. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202201883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
| | | | | | - Makoto Yasuda
- Osaka University Department of Applied Chemistry, Graduate School of Engineering 2-1 Yamadaoka, Suita 565-0871 Osaka JAPAN
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Watson HA, Fielding AJ, Hale KJ. EPR evidence for α-triphenylstannylvinyl radicals in the O-directed hydrostannation of dialkylacetylenes with Ph 3SnH/cat. Et 3B/O 2. Chem Commun (Camb) 2021; 57:7449-7452. [PMID: 34235526 DOI: 10.1039/d1cc01702k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Here we provide definitive EPR evidence for the existence of α-triphenylstannylvinyl radicals in the low temperature O-directed free radical hydrostannation of dialkyl propargylic alcohols with Ph3SnH/cat. Et3B and O2 in PhMe. Isotropic hyperfine splitting patterns and spectral simulations confirm the assignments made. In the case of the α-triphenylstannylvinyl radical (Z)-2, an isotopic 119/117Sn hyperfine coupling constant of 9.5 mT (95 G) was measured along with a 1Hβ hyperfine coupling constant of 1.1 mT.
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Affiliation(s)
- Hamish A Watson
- The School of Chemistry and Chemical Engineering, Queen's University Belfast, Stranmillis Road, Belfast BT9 5AG, Northern Ireland, UK.
| | - Alistair J Fielding
- The School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK.
| | - Karl J Hale
- The School of Chemistry and Chemical Engineering, Queen's University Belfast, Stranmillis Road, Belfast BT9 5AG, Northern Ireland, UK.
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Lu CJ, Chen YT, Wang H, Li YJ. Palladium-catalyzed dearomative allylation of indoles with cyclopropyl acetylenes: access to indolenine derivatives. Org Biomol Chem 2021; 19:635-644. [PMID: 33367392 DOI: 10.1039/d0ob02103b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
A palladium-catalyzed redox-neutral allylic alkylation of indoles with cyclopropyl acetylenes has been disclosed. Various 1,3-diene indolenine framework bearing a quaternary stereocenter at the C3 position were synthesized straightforwardly in good to excellent yields with high regio- and stereoselectivities. The reaction could be further expanded to the dearomatization of naphthols to synthesize functionalized cyclohexadienones with 1,3-diene motifs. The reaction exhibited high atom economy and good functional group tolerance.
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Affiliation(s)
- Chuan-Jun Lu
- College of Chemical Engineering, Zhejiang University of Technology, Chaowang Road 18#, Hangzhou 310014, China. and College of Chemistry and Chemical Engineering, Qingdao University, Qingdao 266071, China
| | - Yu-Ting Chen
- College of Chemical Engineering, Zhejiang University of Technology, Chaowang Road 18#, Hangzhou 310014, China.
| | - Hong Wang
- College of Chemical Engineering, Zhejiang University of Technology, Chaowang Road 18#, Hangzhou 310014, China.
| | - Yu-Jin Li
- College of Chemical Engineering, Zhejiang University of Technology, Chaowang Road 18#, Hangzhou 310014, China.
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