Reductive Enolization in Aldol Addition to Enolizable Aldehydes

Significance

The authors report a new strategy toward forming aldol adducts in the presence of enolizable aldehydes, which relies on forming ­enolates by a magnesium-promoted reduction of α-halo thioesters with Ph₃P. This strategy offers a mild alternative to the traditional stepwise LDA-mediated protocol required for high chemoselectivity in classical aldol additions. The high syn dia­stereoselectivity of this reaction is complementary to the LDA-mediated protocols.