anti-Selective Sc(III)-Catalyzed Sakurai Additions to Glyoxyamide

Significance

The [Sc(S,S)-Phpybox](OTf)₃ complex is an effective catalyst for the enantioselective Sakurai-Hosomi addition of terminally substituted allylsilanes to N-phenylglyoxamide (2). This method offers an alternative to the synthesis of homo­allylic alcohols through the nucleophilic allylation of aldehydes and ketones. The reaction is anti-selective, enantioselective and shows good generality as both aliphatic and aromatic allylsilanes can be used. Aryl-substituted allylsilanes are observed to be more selective than their alkyl-substituted counterparts (97-99% vs 91-95% ee, respectively). Substrates containing either electron-withdrawing or electron-donating substituents in the para position are equally reactive. This protocol provides access to versatile chiral building blocks for β-substituted α-hydroxy and α-amino acids.