Organic Chemistry: Current Research
Open Access

Rh-catalyzed annelation of benzoic acids with α,β-unsaturated ketones

10^th European Organic Chemistry Congress

March 21-22, 2019 | Rome, Italy

Guodong Zhang

Ruhr-University Bochum, Germany

Posters & Accepted Abstracts: Organic Chem Curr Res

Abstract :

Transition metal-catalyzed directed C–H functionalizations have undergone tremendous development, evolving from pioneering examples into robust and versatile tools for modern organic synthesis. Initially, this approach was often limited by the use of complex directing groups. The key advantages of carboxylate directing groups are their broad availability and the fact that they can be removed tracelessly or used as anchor points for further regiospecific C–C or C–heteroatom bond-forming reactions via decarboxylative coupling. Although carboxylate-directed hydroarylation with and α,β-unsaturated ketones has been developed by our group. Still, we believed that many exciting synthetic opportunities would open up, if the carboxylate group could be funneled into new reaction pathways after the hydroarylation step. In the presence of a [Cp*RhCl2]2 catalyst, the Lewis acid In(OTf)3 and the mild base Na2CO3, aromatic carboxylates and α,β-unsaturated ketones undergo a unique hydroarylation/Claisen/retro-Claisen process to give the corresponding indanones. In this carboxylate-directed ortho-C–H annelation, the C–COR bond of the ketone and the CO–OH group of the aromatic carboxylate are cleaved, and the hydroxy group is transferred from the aromatic to the aliphatic acyl residue. This reactivity is synthetically useful particularly when starting from cyclic ketones, which are converted into indanones bearing aliphatic carboxylate side-chains, thus greatly increasing the molecular complexity of aromatic carboxylates in a single step.

Biography :

Guodong Zhang has completed his master degree at the age of 25 years from Zhengzhou University in China. Now he is PhD student in Ruhr-Universität Bochum followed by Lukas J. Gooßen as the supevisor. His current research interests include the transition-metal-catalyzed C–H bond activation and functionalization.