(3R,4S)-1-T-BUTOXYCARBONYL-3-ACETOXY-4-PHENYL-2-AZETIDINONE; (3R,4S)-1-T-Butoxycarbonyl-3-A; (3R,4S)-1-T-BUTOXYCARBONYL-3-ACETOXY -4-PHENYL-2-AZETIDINONE,98+%; SIDE CHAINS OF DOCETAXEL--3; tert-butyl (3R,4S)-3-(acetyloxy)-2-oxo-4-phenylazetidine-1-carboxylate