Rhodium Porphyrins for Catalytic C-H Activation

描述（由申请人提供）：常见但不反应的C-H键到其他官能团的化学选择性转化有可能彻底改变化学合成。本研究的主要目标是开发卟啉铑催化剂来激活和功能化sp3杂化的C-H键。铑（II）卟啉配合物可以在化学计量上激活sp3 C-H键而不是sp2 C-H键，而不需要在底物内引导基团，同时耐受生物活性化合物中存在的官能团类型。本研究将尝试将化学计量过程转化为催化过程，利用氮氧化物自由基将C-H活化产物铑（III）烷基和氢化物转化为铑（II）卟啉和有用的有机产物，即烯烃，从而使该反应得到更广泛的应用。本研究选择氮氧自由基是基于已知这些化合物将一些铑（III）卟啉氢化物转化为铑（II）卟啉的能力，以及氮氧促进铑（III）卟啉烷基转化为烯烃的能力。本文提出的新的氮氧化物自由基可以避免铑（II）卟啉与以前使用的氮氧化物自由基的已知副反应。

DESCRIPTION (provided by applicant): The chemoselective transformation of common but unreactive C-H bonds to other functional groups has the potential to revolutionize chemical synthesis. The primary goal of the proposed research is to develop rhodium porphyrin catalysts to activate and functionalize sp3 hybridized C-H bonds. Rhodium (II) porphyrin complexes can stoichiometrically activate sp3 C-H bonds over sp2 C-H bonds without the need for directing groups within the substrate while tolerating the types of functional groups present in bioactive compounds. This research will attempt to make this reaction more widely applicable by making the stoichiometric process into catalytic one by using nitroxide radicals to turn the products of this C-H activation, rhodium (III) alkyl and hydride species, into rhodium (II) porphyrins and useful organic products, namely alkenes. Nitroxide radicals were chosen for this study based on the known ability of these compounds to covert some rhodium (III) porphyrin hydrides to rhodium (II) porphyrins and the nitroxide promoted conversion of rhodium (III) pophyrin alkyls into alkenes. The new nitroxide radicals proposed herein will allow catalysis by avoiding known side reactions of the rhodium (II) porphyrins with previously used nitroxide radicals.