Exploring Novel Transition-Metal Catalysis: Change the Game

Transition-metal catalysis plays a central role in synthetic organic chemistry. This chemistry provides the most promising way to achieve an environmentally benign process with a high efficiency and selectivity and atom economy. This presentation will highlight how novel and meaningful transition-metal catalysis have been developed by overcoming challenges, designing new mechanism and establishing selectivity.

The first part of the talk shows the transformations of vinylsilanes by using transition metals such as Rh(I) and Ir(I) with HCl for preparing silyl ether (alkoxysilane). With advantageous feature that vinylsilanes are stable enough to introduce various functional groups, the silylation is applied to the formation of organic-inorganic hybrid materials to overcome the problems arisen from conventional silane precursors.

The second part of the talk describes dehydroformylation of aldehydes to generate olefins that features the transfer of a formyl group and hydride from an aldehyde substrate to a strained olefin acceptor. A rhodium(xantphos)(benzoate) catalyst activates aldehyde C–H bonds with high chemoselectivity to trigger C–C bond cleavage and generates olefins at low loadings and temperatures.

The third part of the talk deals with the transformation of α,α-bis(allyl)aldehydes. Desymmetrization has emerged as the way to access chiral quaternary-carbon motifs, which are among the most challenging stereocenters to generate with enantiocontrol. Strategies involving C−H bond activation are especially promising yet rare. Given this challenge, selective Rh-catalyzed desymmetrizations of all-carbon quaternary centers from prochiral α,α-bis(allyl)aldehyde have recently disclosed by systemic ligand control.

The last chemistry shows unprecedented intermolecular three-component aminoarylation of alkyne by palladium catalysis. This reaction overcomes well-known, established transformations by delicate design of the reaction system, and is accessible the key intermediates of natural products and medicinal compounds.

20181012_화학과 특별세미나_박정우박사.pdf