Stannatrane coupling reaction

A noteworthy sp -sp coupling was reported in the synthesis of the antibiotic carbapenem 124, which was developed by chemists at Merck (Scheme 5.4.24).i2i in this reaction, carbapenem triflate 121 reacted with stannatrane 122 to give 123. The stannatranes were designed by Vedejs to facilitate the selective coupling of alkyl groups. 

Scheme 5.4.24 Stille reaction in the synthesis of the antibiotic carbapenem 124 by using stannatrane 122 as coupling partner (TES triethylsilyl)...

Process research efforts relative to the design of a practical synthesis of a structurally complex MRSA carbapenem (1) culminated in the establishment of two distinct synAeses. The first is based on a unique Stille coupling between a carbapenem enol triflate and a stannatrane appended via a methylene spacer to a complex and extended heteroaromatic side chain. The second is founded upon a novel n-allyl palladium reaction to incorporate die entire complex side chain. Details on die development of both methods are described. 

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