摘要：

The TiCl4-mediated reactions of allyltrimethylsilane (Sakurai reaction) with cyclic enones 3-7 have been investigated. The stereochemistry of these reactions has been compared with the stereochemistry of the copper-catalyzed conjugate addition of n-propylmagnesium bromide with the same set of enones. It is shown that the major products formed in the Sakurai reactions are those favored on stereoelectronic grounds. In each case the copper-catalyzed Grignard addition affords less of the stereoelectronically preferred product, presumably as a result of steric hindrance to approach of the bulky cuprate cluster to the Lewis acid coordinated enone.

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