Organocatalytic enantioselective Mannich-type reaction of phosphorus ylides:: Synthesis of chiral N-Boc-β-amino-α-methylene carboxylic esters

The first asymmetric Mannich-type reaction of stabilized phosphorus ylides and N-Boc aldimines was described promoted by a readily available and recyclable chiral bisthiourea organocatalyst. Subsequent reaction with formalin smoothly provides N-Boc-beta-amino-alpha-methylene carboxylic esters in a highly enantiomerically enriched form (up to 96% ee).