Exploration of novel paradigms in metal-free catalysis

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There has been great interest in the past few years in the design of novel and green technologies to replace catalytic systems that rely mainly on expensive and toxic noble metals. As such, most researchers have been focusing their work on using base metals rather than second- and third-row transition elements (rhodium, iridium, platinum, palladium). Another promising approach consists of using Frustrated Lewis Pair (FLPs), a popular concept termed by Douglas Stephan to explain the reactivity of Lewis pairs prevented from forming adducts by steric or geometric constraints, as metal-free catalysts. These species can provide cheap, green and non-toxic alternatives to current industrial technologies. Our 10-year experience in the synthesis and reactivity of ambiphilic molecules (molecules having both Lewis acid and Lewis basic moieties in the framework) allows us to have a unique look on metal-free catalysis. Based on some important results we reported recently in FLP catalysis and on our knowledge of organometallic catalysis, we propose three hypotheses that will guide the development of efficient metal-free catalysts. Our program involves using these paradigms, with the help of computational work, to design and synthesize FLPs with tailored Lewis acidity and basicity to use as catalyst in industrially-relevant applications. The transformations that we propose to investigate in this proposal are amongst the most useful in synthetic chemistry and in the pharmaceutical industry. It will include the reduction of carbonyl moieties to alcohols, the catalytic C-H bond functionalization of arenes and alkanes, and the hydroamination of alkynes. The demonstration of the concepts presented in this proposal will allow the community to use FLPs for many other catalytic processes and make this technology a viable replacement for transition metals in 2-electron transfer processes.