Corey-Myers synthesis

Several vinylcyclopropane to cyclopentene rearrangements have been reported in which a cationic substituent appears to facilitate the reaction. For example, exposure of (150 equation 23) to excess di-ethylaluminum chloride at 0 C for 12 min furnished (151), which served as a key intermediate in Corey and Myers synthesis of the plant hormone antheridogen-An. Attempts to effect this transformation thermally were unsuccessful. In a similar fashion, treatment of (152 equation 24) with boron tribromide induced VCP rearrangement of this compound at room temperature, probably via initial cleavage to the allylic carbocation (153). The reaction of the analogous vinylcyclopropane lacking a phenyl group failed to go to completion under these conditions. 

Corey, E.J., and A.G. Myers Total Synthesis of (+ )-Antheridium-Inducing Factor-(Aad, 2) of the Fern Anemia phyllitidis. Clarification of Stereochemistry. J. Amer. Chem. Soc. 107, 5574 (1985). 

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