Stereoselective synthesis of 1-methylcarbapenem precursors : studies on the diastereoselective hydroformylation of 4-vinyl b-lactam with aminophosphonite–phosphinite and aminophosphine–phosphite rhodium(I) complexes

The asymmetric hydroformylation of variously N-substituted 4-vinyl -lactams catalyzed by rhodium aminophosphonite-phosphinite and rhodium aminophosphine-phosphite complexes was studied. The products are valuable intermediates in the preparation of 1-methyl carbapenem antibiotics; the stereoselectivity to the desired -isomer is related to the presence of a substituent at the N atom of the -lactam ring. The regioselectivity (branched/linear) but not the stereoselectivity () was found to be dependent on the substrate to catalyst ratio.