A regioselective reductive cleavage of benzylidene acetal: stereoselective synthesis of N-Boc-protected cis-(2R,3S)-3-hydroxy pipecolic acid

A stereoselective synthesis of N-Boc-protected cis-(2R,3S)-3-hydroxy pipecolic acid, starting from d-glucose is described. The key step in the overall synthesis is a highly regioselective reductive cleavage of benzylidene acetal 13 leading to hydroxymethyl piperidine derivative 14.