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Selective Synthesis of Epolactaene Featuring Efficient Construction of Methyl (Z)-2-Iodo-2-butenoate and (2R,3S,4S)-2-Trimethylsilyl-2,3-epoxy-4-methyl- γ-butyrolactone

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journal contribution
posted on 22.06.2006, 00:00 by Ze Tan, Ei-ichi Negishi
(+)-Epolactaene was synthesized in 14 steps in the longest linear sequence. The synthesis is highlighted by a highly efficient preparation of the lactone intermediate 4, which only requires three steps from the commercially available (S)-3-butyn-2-ol. It also features a fully stereocontrolled synthesis of the intermediate 9, which was constructed through the use of Zr-catalyzed methylalumination of alkynes and a series of Pd-catalyzed organozinc cross-coupling reactions, such as homopropargylation, direct ethynylation, and alkenylation of the methyl ester of (Z)-α-iodocrotonic acid (3).