Nickel-Catalyzed Homo- and Cross-Coupling of Allyl Alcohols via Allyl Boronates
作者:Yi Gan、Hui Hu、Yuanhong Liu
DOI:10.1021/acs.orglett.0c01424
日期:2020.6.5
allylic alcohols to 1,5-dienes in the presence of B2pin2 with excellent regioselectivity has been developed. Mechanistic studies indicate that the reaction proceeds via sequential nickel-catalyzed borylation of allylalcohols followed by cross-coupling of the resulting allyl boronates with allylalcohols. The method was effectively applied to nickel-catalyzed allylation of aldehydes using allylic alcohols
through asymmetric reduction of ketones or kineticresolution of secondaryalcohols, enantioselective synthesis of the corresponding secondaryalcohols is challenging when the two groups attached to the prochiral or chiral centers are spatially or electronically similar. For examples, dialkyl (sp3 vs. sp3), diaryl (sp2 vs. sp2), and aryl-alkenyl (sp2 vs. sp2) alcohols are difficult to produce with high enantioselectivities
The borrowing-hydrogen (or hydrogen autotransfer) process, where the catalyst dehydrogenates a substrate and formally transfers the H atom to an unsaturated intermediate, is an atom-efficient and environmentally benign transformation. Described here is an example of an asymmetric borrowing-hydrogen cascade for the formal anti-Markovnikov hydroamination of allyl alcohols to synthesize optically enriched
Nickel-Catalyzed Alkylation or Reduction of Allylic Alcohols with Alkyl Grignard Reagents
作者:Bo Yang、Zhong-Xia Wang
DOI:10.1021/acs.joc.0c00008
日期:2020.4.3
selective alkylation and reduction of allylicalcohols with alkyl Grignard reagents were performed. The reaction using Ni(dppe)Cl2 as the catalyst resulted in the cross-coupling of allylicalcohols with primary alkyl Grignard reagents and cyclopropylmagnesium bromide. The reaction catalyzed by the combination of Ni(PCy3)2Cl2 and dcype led to the reduction of allylicalcohols. Secondary alkyl Grignard
Synthesis of Allylsilanes via Nickel-Catalyzed Cross-Coupling of Silicon Nucleophiles with Allyl Alcohols
作者:Bo Yang、Zhong-Xia Wang
DOI:10.1021/acs.orglett.9b02946
日期:2019.10.4
NiCl2(PMe3)2-catalyzed reaction of allylalcohols with silylzinc reagents, including PhMe2SiZnCl, Ph2MeSiZnCl, and Ph3SiZnCl, was performed, achieving allylsilanes in high yields. Aryl- and heteroaryl-substituted allylalcohols, (E)-3-arylprop-2-en-1-ols, 1-aryl-prop-2-en-1-ols, and (E)-1-phenylpent-1-en-3-ol can be employed in the transformation. A range of functional groups as well as heteroaryl