Efficient one-step aldol-type reaction of ketones with acetals and ketals mediated by dibutylboron triflate/diisopropylethyl amine.

one-step Mukaiyama aldol type reaction [reaction: see text] A highly efficient one-step Mukaiyama aldol-type reaction has been developed for the synthesis of beta-alkoxy carbonyl compounds starting from ketones and acetals/ketals. The reaction is mediated by a combination of Bu(2)BOTf and i-Pr(2)NEt affording the products in high yields. Formation of the two possible diastereoisomers of the beta-alkoxy ketones from the chiral acetals shows that the condensation takes place by an S(N)1 mechanism, involving prior opening of the acetal to an oxonium ion.