The stereoselective and convergent synthesis of the C12–C28 segment 2 of the apoptosis inducing macrolide antibiotic, apoptolidin (1), is described. The synthesis involves a highly stereoselective tin(II)-mediated aldol reaction between the C17–C22 ethyl ketone 3 and the C23–C28 aldehyde 4 as the key step.
Overman/Claisenrearrangement of an allylic 1,2-diol is reported. The enantiopure allylic 1,2-diol was efficiently prepared from naturally occurring dimethyl tartrate. The chirality transfer reactions through two consecutive [3,3]-sigmatropic rearrangements proceeded with complete diastereoselectivity in a one-pot process. The enantioselective total synthesis of (–)-stemoamide using Overman/Claisen rearrangement