Insight into Rh(I)-catalyzed cyclization of 6-octen-1-als with a chiral protecting group
Rh(I)(Wilkinson)[ClRh(PPh3)3]-catalyzed cyclization of 6-octen-als with a chiral protecting group at the C2-position afforded only cis-cyclohexanol derivatives, and in the case of C4-position yielded a mixture of cis and trans cyclohexanol. These findings were remakably different from the case of the C3-position, in which the trans cyclohexanol derivative was obtained. Wilkinson's complex acts as [ClRh(PPh3)3] a Lewis acid, and this bulkier Lewis acid affords higher diastereoselectivity. Rh(I)-catalyzed cyclization of 6-octen-1-al derivatives is not affected by chiral ligands.