Takemoto-Tanaka total synthesis

Kitahara also accomphshed the total synthesis of 6a according to the method described by the Takemoto-Tanaka group in which the final formation of the nine-membered ring was achieved by RCM using Grubbs catalyst (Scheme 5.32) [82]. In their synthesis, the precursor 89 was prepared by the convergent synthetic strategy. 

Takemoto, Y, Baba, Y, Saha, G., Nakao, S., Iwata, C., Tanaka, T., and Ibuka, T. (2000) Asymmetric total synthesis of halicholactone. Tetrahedron Lett., 41, 3653-3656. 

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