Asymmetric indium-mediated Barbier-type allylation reactions with ketones to form homoallylic alcohol products

摘要

We report a general method for the enantioselective allylation of both aromatic and aliphatic ketones under indium-mediated Barbier-type conditions.Using 2 equiv of a commercially available amino alcohol,either (1S,2R)-(+)-2-amino-l,2-diphenylethanol ((+)-l) or (1R,2S)-(-)-2-amino-l,2-diphenylethanol ((-)-l) as the chiral auxiliary,good yields and enantioselectivities were achieved.To our knowledge,the enantioselectivities reported herein are the highest obtained for the indium-mediated allylations of ketones,specifically the homoallylic alcohol product obtained from the addition to alpha,alpha,alpha-trifluoroacetophenone provided 80% enantiomeric excess.