Desymmetrization of cyclohexanes by site- and stereoselective C-H functionalization

Carbon-hydrogen (C-H) bonds have long been considered unreactive and are inert to traditional chemical reagents, yet new methods for the transformation of these bonds are continually being developed.sup.1-9. However, it is challenging to achieve such transformations in a highly selective manner, especially if the C-H bonds are unactivated.sup.10 or not adjacent to a directing group.sup.11-13. Catalyst-controlled site-selectivity--in which the inherent reactivities of the substrates.sup.14 can be overcome by choosing an appropriate catalyst--is an appealing concept, and substantial effort has been made towards catalyst-controlled C-H functionalization.sup.6,15-17, in particular methylene C-H bond functionalization. However, although several new methods have targeted these bonds in cyclic alkanes, the selectivity has been relatively poor.sup.18-20. Here we illustrate an additional level of sophistication in catalyst-controlled C-H functionalization, whereby unactivated cyclohexane derivatives can be desymmetrized in a highly site- and stereoselective manner through donor/acceptor carbene insertion. These studies demonstrate the potential of catalyst-controlled site-selectivity to govern which C-H bond will react, which could enable new strategies for the production of fine chemicals.Unactivated cyclohexane derivatives can be desymmetrized by site- and stereoselective C-H functionalization using carbene-insertion chemistry.
Author(s): Jiantao Fu [sup.1] , Zhi Ren [sup.1] , John Bacsa [sup.1] , Djamaladdin G. Musaev [sup.1] [sup.2] , Huw M. L. Davies [sup.1] Author Affiliations:(1) Department of Chemistry, Emory [...]