Iron-Catalyzed C—C Bond Formation by Direct Functionalization of C—H Bonds Adjacent to Heteroatoms

摘要

Transition-metal-catalyzed C—H functionalization for the atom- and step-economical synthesis of functional molecules has attracted tremendous efforts in both academia and industry. The advantages of this method are the high efficiency, low cost, and minimal environmental impact. Heteroatom-containing molecules are abundant in natural products, pharmaceuticals, and materials. It is highly desirable to synthesize these molecules and their derivatives by direct C—H functionalization. Metal carbene insertion into a C-H bond adjacent to an oxygen atom presents an efficient synthetic approach to ether derivatives (Scheme 1, Meth-od A). The addition of carbon radicals to C(sp~2)=X bonds is another useful synthetic tool for the formation of C-C bonds in organic synthesis (Scheme 1, Method B). The groups of Li and Sames reported C—C bond formation by C—H bond activation adjacent to an oxygen atom (Scheme 1, Method C). Furthermore, our group and others reported direct functionalization of C—H bonds adjacent to either a sulfur or nitrogen atom. Although these methods are efficient for C—H functionalization, a practical and efficient method toward such a transformation is still a challenge in synthetic chemistry.