Double stereodifferentiating crotylation reactions with α-amino aldehydes: Asymmetric synthesis of vicinal amino alcohol synthons

The sense and level of 1,2-asymmetric induction have been evaluated in the BF3·OEt2 promoted addition of (E)-crotylsilanes (R)-1 and (S)-1 to α-amino aldehydes 2a through 2d. The sense of carbonyl diastereoface selectivity was shown to be dependent of the chirality of the silane reagent.