4- Acetoxy-P-lactam

It is well known that the most direct access to 4-acetoxy-P-lactams is the addition of CSI to the corresponding vinyl acetate [17]. Kametani and coworkers [18] were the first to accomplish the total synthesis of antibiotic ( ) PS-5 by reaction between 3-ethyl-4-acetoxyazetidin-2-one 12 and the lithium enolate of r-butyl a-diazoacetylacetate and further ring closure in the resulting p-lactam 15 by the carbene insertion reaction developed by Merck (Scheme 2). The same authors [19] reported the synthesis of antibiotic ( ) PS-6 starting from the corresponding 4-acetoxyazetidin-2-one 13. 

Additionally to the above described acid chloride-imine methodology we [46] and others [47] considered alternative pathways toward the synthesis of 4-acetoxy p-lactams 79 (Scheme 13). Georg has reported on the utilization of... 

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