Asymmetric Methallylation of Ketones Catalyzed by a Highly Active Organocatalyst 3,3′-F2-BINOL
摘要:
(S)-3,3'-F-2-BINOL has been synthesized for the first time and demonstrated as a highly active organocatalyst for asymmetric methallylation of ketones. Up to 98:2 enantioselectivity and 99% yield were obtained with 5 mol % catalyst loading. The catalyst (S)-3,3'-F-2-BINOL could be easily recovered and reused.
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