Diastereoselective addition of chiral azomethine ylides to cyclic α,β-unsaturated N-enoylbornanesultams

Doubly diastereoselective 1,3-dipolar cycloaddition reactions of chiral non-racemic azomethine ylides to cyclic five- and six-membered, alpha,beta-unsaturated N-enoylbornanesultams were carried out. When suitable solvents were used, the fused bicyclic adducts formed were obtained in good diastereoselectivity. Moreover, a change of the absolute configuration of the starting ylide precursor reversed the diastereoselectivity of some such reactions. Cleavage of the chiral auxiliary of the cycloadducts furnished amino alcohols and a beta-amino ester. The latter was transformed into a known precursor of an antibacterial compound.