abstract |
Optically active acyloxyazetidinones of the formula and acylazetidinones of the formula wherein R, hydrogen or lower alkyl, R 2 is dimethyl- (2,3-dimethylbut-2-yl) silyl, R 3 is methyl and R 4 is hydrogen or an amino protecting group R ' 4 , and process for their preparation. The compounds of the formulas I and II are used as intermediates in penem synthesis. |