(-)-(2R,3S)-3-[(tert-butyloxycarbonyl)amino]-2-(benzyloxy)butan-1-ol

(+)-(3R,4S)-1-(4-methoxyphenyl)-3-benzyloxy-4-hydroxymethyl-2-azetidinone

(-)-(3R,4S)-trans-3-benzyloxy-4-formyl-1-(p-methoxyphenyl)-2-azetidinone

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

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