Organocatalytic Asymmetric Alkylation of Aldehydes by SN1-Type Reaction of Alcohols
作者:Pier Giorgio Cozzi、Fides Benfatti、Luca Zoli
DOI:10.1002/anie.200805423
日期:2009.2.2
Work‐alcoholic! The elusive enantioselective catalytic α‐alkylation of aldehydes, a widely sought transformation, was brought to execution by the use of alcohols capable of forming stabilized carbocations (see scheme, TFA=trifluoroacetic acid).
Organocatalytic Stereoselective α-Alkylation of Aldehydes with Stable Carbocations
作者:Fides Benfatti、Elena Benedetto、Pier Giorgio Cozzi
DOI:10.1002/asia.201000160
日期:2010.9.3
stereoselective alkylation of aldehydes is carried out with the four stable carbocations 1, 2, 3, 4 in the presence of a catalytic amount (20 mol%) of MacMillan imidazolidinones 5, 6. In all reactions, lutidine was used as a base. The alkylation reactions are investigated at different temperatures with linear and branched aldehydes. In the case of carbocation tropyliumfluoroborate, an interesting