The asymmetric synthesis of (2S,3R)-capreomycidine

An improved asymmetric synthesis of the guanidine-containing amino acid (2S,3R)-capreomycidine has been achieved in seven steps and 28% overall yield. The key synthetic step involved a Mannich-type reaction between a chiral glycine aluminum enolate and the benzyl-imine of 3-tert-butyldimethylsiloxy-propionaldehyde.