Reversal of stereochemistry in a two-step Staudinger reaction by changing the backbone protecting group. Synthesis of NH-trans-3-benzoyloxy-4-aryl-azetidinones

Article abstract of DOI:10.1016/S0040-4039(99)01800-6

Changing the protecting group in the glyoxylic acid derived ketene from benzyloxy to benzoyloxy provides a simple way of switching the diastereoselectivity of the substituents on the final β-lactam ring from cis to trans.