Reversal in enantioselectivity induced by achiral alcohols in asymmetric autocatalysis in the presence of a chiral diol as a chiral initiator

A reversal in enantioselectivity was observed by the combination of a chiral diol and achiral alcohols as a chiral initiator in the asymmetric alkylation of a pyrimidine-5-carbaldehyde using diisopropylzinc. (2S,3S)-Butane-2,3-diol alone induced (R)-pyrimidyl alkanol, while a mixture of the chiral diol and phenol derivatives induced (S)-pyrimidyl alkanol. The effect of achiral alcohols is also discussed. (c) 2012 Elsevier Ltd. All rights reserved.