Rhodium Porphyrins for Catalytic C-H Activation

描述(由申请人提供)：普通但非活性的C-H键到其他官能团的化学选择性转化有可能使化学合成发生革命性的变化。本研究的主要目标是开发能够活化和官能化SP3杂化C-H键的催化剂。Rh(II)卟啉络合物可以化学计量地激活sp2 C-H键上的sp3 C-H键，而不需要在底物中直接基团，同时容忍生物活性化合物中存在的官能团的类型。本研究试图通过使用氮氧自由基将C-H活化的产物Rh(III)烷基和氢化物转化为Rh(II)卟啉和有用的有机产物，即烯烃，使化学计量过程成为催化过程，从而使该反应更广泛地适用。本研究选择了氮氧基，这是基于这些化合物已知的将某些Rh(III)卟啉氢化物转化为Rh(II)卟啉的能力，并且氮氧化物促进了Rh(III)并联烷基向烯烃的转化。这里提出的新的氮氧自由基将通过避免已知的Rh(II)卟啉与先前使用的氮氧自由基的副反应来实现催化。

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.