Thienamycin Total Synthesis. 2. Model Studies - Synthesis of a Simple 2-(Alkylthio)carbapen-2-em

Article abstract of DOI:10.1021/jo01294a043

Model studies directed toward the total synthesis of (+/-)-thienamycin are described which have resulted in the preparation of the benzyl ester of (+/-)-2-(methylthio)carbapen-2-em-3-carboxylic acid (2).Azetidinone 3 was converted into thioenolether 24 via thioacetal 6.Bromination of 24 followed by treatment with base afforded the key bicyclic intermediate 25.Dehydrobromination, decarbalkoxylation, and isomerization of the double bond then yielded the desired model compound 2.The synthesis of carbapenams 19a,b (R = t-Bu and Bz) from azetidinone 11 is also described.