Organic Letters 2005-01-20

New reagent system for attaining high regio- and stereoselectivities in allylic displacement of 4-cyclopentene-1,3-diol monoacetate with aryl- and alkenylmagnesium bromides.

Yuichi Kobayashi, Kenya Nakata, Takayuki Ainai

Index: Org. Lett. 7(2) , 183-6, (2005)

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Abstract

[Reaction: see text] Low regioselectivity of RMgBr (R = aryl, alkenyl) in the CuCN-catalyzed reaction with 4-cyclopentene-1,3-diol monoacetate is improved by addition of LiCl or MgCl2 to a similar extent as previously obtained with RMgCl (>90:10). The limitation encountered in the preparation of RMgCl no longer exists in the present method using RMgBr. The method is utilized in the synthesis of AH-13205, a selective EP2-receptor agonist.