"Frustrated Lewis Pairs": Metal-Free Synthesis and Catalysis

点击翻译按钮获取中文摘要

Frustrated Lewis Pairs Chemistry In a seminal Science article, we reported the heterolytic cleavage of H2 without using a transition metal. That finding opened the door to metal-free hydrogenation catalysis and spawning world-wide activity in the general area of “frustrated Lewis pairs” (FLPs) chemistry. We have extended the applications of FLPs in stoichiometric chemistry, as well as in catalysis, repeatedly finding shocking examples of the ability of non-metal systems to provide new and interesting ways to effect transformation. In this proposal, we are focused on three major areas for new developments: (i) the development and exploration of new types of Boron-donor FLPs and their utility (ii) the applications of FLPs in stoichiometric and catalytic reactivity and (iii) the development of phosphorus-based Lewis acids, their reactivity and the implication of such systems. In (i) we probed new synthetic route including CO-reduction, click-chemistry, to boron-based FLPs and explore the resulting reactivity. Borenium cations and interesting metal-based FLPs in which the ligand is ancillary are also developed. In (ii) we propose an expansion of FLP-aromatic hydrogenation to applications in organic synthesis, while “frustrated radical pairs” (FRPs) are employed to effect C-H bond activations. The recent development of FLP-hydroamination catalysis will be expanded to hydrophosphination or hydrothiolation of alkynes and olefins and the catalytic reductions of CO2 will be refined to employ H2 as the reductant. In (iii) we exploit our most recent Science article to develop phosphonium-based Lewis acids to elaborate such systems for applications in Lewis acid catalysis as these sigma*-acceptors are expected to be functional group tolerant, paving the way to widespread applications. We also envision the use of P-based Lewis acids in FLP chemistry. Moreover, we will also probe hydrogenation of phosphorus heterocycles raising the promise of an unprecedented organo-catalytic route to the hydrogenation of organic substrates employing H2 directly.