Preparation of cyclic alkenylmagnesium reagents via an iodine/magnesium exchange

The reaction of various cyclic alkenyl iodides with i-PrMgCl·LiCl produces the corresponding alkenylmagnesium reagents under mild conditions. After reaction with various electrophiles, like allylic halides, disulfides, aldehydes and acid chlorides, the expected products are obtained in 53–91% yield. Remarkably, the mild conditions of the I/Mgexchange tolerate the presence of sensitive diene functionalities.