The Mechanism and an Improved Asymmetric Allylboration of Ketones Catalyzed by Chiral Biphenols
作者:David S. Barnett、Philip N. Moquist、Scott E. Schaus
DOI:10.1002/anie.200904715
日期:2009.11.2
Giving it a boost: A mechanistic study of the enantioselective asymmetric titled reaction with allyldiisopropoxyborane catalyzed by chiralbiphenols revealed a key ligand exchange process which liberates isopropyl alcohol. The addition of iPrOH to the reaction increases the overall rate and enantioselectivity. As a result an improved reaction, employing allyldioxaborinane with 1 and tBuOH, resulted
Synthesis and Application of Substituted 1,16-Dihydroxytetraphenylenes in Catalytic Asymmetric Allylboration of Ketones
作者:Guo-Li Chai、Bo Zhu、Junbiao Chang
DOI:10.1021/acs.joc.8b02475
日期:2019.1.4
The synthesis and application of a newly designed C2-symmetric chiral-substituted 1,16-dihedroxytetraphenylene (DHTP) is reported. Efficient syntheses of enantiopure substituted DHTP were accomplished, and these enantiopure compounds were used as organocatalysts in asymmetric allylboration of ketones under very mild conditions. Accordingly, several tertiary alcohols were generated in moderate to good
One-Pot Asymmetric Synthesis of Alkylidene 1-Alkylindan-1-ols Using Brønsted Acid and Palladium Catalysis
作者:Réka J. Faggyas、Ewen D. D. Calder、Claire Wilson、Andrew Sutherland
DOI:10.1021/acs.joc.7b02287
日期:2017.11.3
2-bromoaryl ketones has been developed for the asymmetric synthesis of 3-methyleneindanes bearing a tertiary alcohol center. Brønsted acid-catalyzed allylboration with a chiral BINOL derivative was followed by a palladium-catalyzed Mizoroki–Heck cyclization, resulting in selective formation of the exo-alkene. This novel protocol provides a concise and scalable approach to 1-alkyl-3-methyleneindan-1-ols
We disclose herein an efficient enantioselective Barbier-type allylation of ketones usingallylhalide and indium metal in water. The reaction was catalysed by chiral bis(imidazoline) to afford homoallylic alcohols having quaternary stereocenters in good yield with moderate to good enantioselectivity. Based on experimental investigation, a possible transition state has been proposed to explain the