Reaction maitotoxin

Tandem carbonyl olefmation—olefm metathesis utilizing the Tebbe reagent or dimethyl-titanocene is employed for the direct conversion of olefmic esters to six- and seven-mem-bered cyclic enol ethers. Titanocene-methylidene initially reacts with the ester carbonyl of 11 to form the vinyl ether 12. The ensuing productive olefm metathesis between titano-cene methylidene and the cis-1,2 -disubstituted double bond in the same molecule produces the alkylidene-titanocene 13. Ring-closing olefin metathesis (RCM) of the latter affords the cyclic vinyl ether 14 (Scheme 14.8) [18]. This sequence of reactions is useful for the construction of the complex cyclic polyether frameworks of maitotoxin [19]. 

Bernard, V, Laurent, A., Derancourt, I, Clement-Durand, M., Picard, A., Le Peuch, C., Berta, P, and Doree, M. 1988. Maitotoxin triggers the cortical reaction and phosphatidylinositol-4,5- bisphosphate breakdown in amphibian oocytes. Eur J Biochem 174, 655-662. 

Trevino, C.L., De la Vega-Beltran, J.L., Nishigaki, T, Eelix, R., and Darszon, A. 2005. Maitotoxin potently promotes Ca(2+) influx in mouse spermatogenic cells and sperm, and induces the acrosome reaction. J Cell Physiol, Epub. 

The coupling of the enol triflate 74 with the stannyl enol ether 75 proceeded rapidly at room temperature to give 76 in good yield in the presence of (2uCl as an additive, which plays a crucial role for the success of the coupling. The reaction has been utilized extensively for the construction of polyether systems of marine natural products such as maitotoxin [35]. 

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