Journal of Organic Chemistry 2007-04-13

Total synthesis of borrelidin.

Tohru Nagamitsu, Daisuke Takano, Kaori Marumoto, Takeo Fukuda, Kentaro Furuya, Kazuhiko Otoguro, Kazuyoshi Takeda, Isao Kuwajima, Yoshihiro Harigaya, Satoshi Omura

Index: J. Org. Chem. 72 , 2744, (2007)

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Abstract

The total synthesis of borrelidin has been achieved. The best feature of our synthetic route is macrocyclization at C11-C12 for the construction of an 18-membered ring after esterification between two segments. A detailed examination of the macrocyclization led us to the samarium(II) iodide-mediated intramolecular Reformatsky-type reaction as the most efficient synthetic approach. The two key segments were synthesized through regioselective methylation, directed hydrogenation, stereoselective Reformatsky-type reaction, and MgBr2.Et2O-mediated chelation-controlled allylation.