Transition Metal-Free Dehydrogenative C-C And C-X Bond Forming Reactions

The direct formation of C-C/C-X bonds from unfunctionalized C-H/X-H bonds is termed as cross-dehydrogenative coupling (CDC). \ud C-C/ C-X bond formation reactions are the most important processes in organic chemistry1(a,b,c). These reactions have proven very useful tools for organic chemists allowing the selective coupling of C-C or C-X bonds. The conventional crosscoupling methods must use pre-functionalized starting materials, such as organic (pseudo) halides or organometallic (Sn, Mg, Zn, etc.) reagents.2 The major drawback is in terms of environmental cost that is many cross-coupling reactions requiring a trasmetallation step concurrently generate a stoichiometric amount of metal salt as waste. For example, Negishi (Zn), Stille (Sn), Kumad (Mg), Fukuyama (Zn), and Suzuki (B).Cross-dehydrogenative coupling (CDC) would eliminate the preparation of functional groups and thus make synthetic schemes shorter and more efficient, highly desirable features for the next generation of C/C-X bond formations. Even though several transition-metals employed for CDC reactions, iodine catalyzed CDC reactions have emerged as a powerful tool for the selective construction of C-C/C-X bonds as well as an integral part of organic synthesis.3 One reason for the great success of coupling reactions is the predictable regioselectivity of the C-C/C-X bond formation