Stereoselective synthesis of spiro-β-lactams using d-(+)-glucose derived chiral pool: remarkable influence of the torquoelectronic effect

Diastereoselective synthesis of spiro-β-lactams via [2+2] cycloaddition reaction of imines and chiral ketenes is described. The chiral ketene was prepared from commercially available, inexpensive d-glucose. Although, theoretically four diastereomers are possible, the reaction yielded only two diastereomers stereoselectively in good to moderate yields. The stereochemical outcome of the reaction was in accordance with the torquoelectronic model.