97276-83-0Relevant academic research and scientific papers
Catalytic Asymmetric Synthesis of Cyclohexanes by Hydrogen Borrowing Annulations
Armstrong, Roly J.,Akhtar, Wasim M.,Young, Tom A.,Duarte, Fernanda,Donohoe, Timothy J.
, p. 12558 - 12562 (2019/08/16)
Hydrogen borrowing catalysis serves as a powerful alternative to enolate alkylation, enabling the direct coupling of ketones with unactivated alcohols. However, to date, methods that enable control over the absolute stereochemical outcome of such a process have remained elusive. Here we report a catalytic asymmetric method for the synthesis of enantioenriched cyclohexanes from 1,5-diols via hydrogen borrowing catalysis. This reaction is mediated by the addition of a chiral iridium(I) complex, which is able to impart high levels of enantioselectivity upon the process. A series of enantioenriched cyclohexanes have been prepared and the mode of enantioinduction has been probed by a combination of experimental and DFT studies.
Chiral Synthesis via Organoboranes. 4. Synthetic Utility of Boronic Esters of Essentially 100percent Optical Purity. Synthesis of Homologated Boronic Acids and Esters of Very High Enantiomeric Purities
Brown, Herbert C.,Naik, Ramachandra G.,Bakshi, Raman K.,Pyun, Chongsuh,Singaram, Bakthan
, p. 5586 - 5592 (2007/10/02)
2-Alkyl-1,3,2-dioxaborinanes, R*BO2(CH2)3, of essentially 100percent optical purity, prepared by the asymmetric hydroboration of readily available prochiral olefins with subsequent removal of the chiral auxiliary, can be homologated to α-chloroalkyl derivatives, R*CHClBO2(CH2)3, of essentially 100percent ee by reaction with LiCHCl2.The intermediates R*CHClBO2(CH2)3 are smoothly reduced with KIPBH to give the corresponding one-carbon-homologated boronic esters R*CH2BO2(CH2)3 in very high optical purity.The operation can be repeated to produce R*CH2CH2BO2(CH2)3 etc.Consequently, it is now possible to synthesize a wide variety of optically active boronic esters, not available by direct asymmetric hydroboration, either (+) or (-), in essentially 100percent ee, and to convert these into synthetically valuable compounds.
