(+)-(3R,4S)-1-(tert-butyloxycarbonyl)-4-methyl-3-(benzyloxy)-2-azetidinone

(2R,3S)-3-[(tert-butyloxycarbonyl)amino]-2-(benzyloxy)butanal

(+)-(3R,4S)-1-(p-anisyl)-4-methyl-3-(benzyloxy)-2-azetidinone