(3S,4R,1'E,2''R,3''S)-4-(3'-tert-butyldimethylsilyloxy-2'-methylprop-1'-ethyl)-3-<3'',4''-di(tert-butyldimethylsilyloxy)-2''-methyl-1''-oxobutyl>-3-methylazetidin-2-one

(3S,4S,5R,6R,1'R,2'E)-4-tert-butyldimethylsilyloxy-3-(4'-tert-butyldimethylsilyloxy-1'-ethylcarbonylamino-3'-methylbut-2'-enyl)-3,5-dimethyl-6-prop-2''-enyltetrahydropyran-2-one

(3S,4R,2'R,3'R,1''E)-1-tert-butyldimethylsilyl-3-(3'-tert-butyldimethylsilyloxy-2'-methyl-1'-oxohex-5'-enyl)-4-(3''-tert-butyldimethylsilyloxy-2''-methylprop-1''-enyl)-3-methylazetidin-2-one

(3S,4R,1'E,2''R,3''S)-1-(tert-butyldimethylsilyl)-4-(3'-tert-butyldimethylsilyloxy-2'-methylprop-1'-ethyl)-3-<3'',4''-di(tert-butyldimethylsilyloxy)-2''-methyl-1''-oxobutyl>-3-methylazetidin-2-one