A Formal Synthesis of Ionomycin Featuring a Permanganate-Mediated Oxidative Cyclisation

Yingfa Li, John P. Cooksey, Zhanghua Gao, Philip J. Kocieński, Stephen M. McAteer & Thomas N. Snaddon
Key steps in a synthesis of the C17-C32 fragment of iono­mycin are (a) an auxiliary-directed oxidative cyclisation of a diene with potassium permanganate to construct a tetrahydrofuran ring and four stereogenic centres in a single operation, and (b) a chain-appendage reaction featuring the alkylation of an enolsilane by an oxocarbenium ion generated from a 2-phenylsulfonyl-substituted tetrahydrofuran.