Iron Porphyrins catalyzed oxidative C-N and C-O bond formation reactions

Abstract

There is a surge of interests in iron-catalysed oxidative C-H functionalization reactions due to the biocompatibility of iron which is an earth abundant metal and hence is appealing in the development of useful sustainable catalysis for fine chemical industries [1]. Our recent works revealed that iron porphyrins can catalyze a variety of nitrene transfer reactions for oxidative C-N bond formation reactions [2-3]. With organic azide as nitrene source, [Fe(F20TPP)Cl] efficiently catalyses intermolecular amination of aliphatic, allylic and benzylic C-H bonds in moderate to high product yields. It is an effective catalyst for intramolecular nitrene C-H bond insertion of aryl azides that can be used to construct a broad spectrum of alkaloids including indoles, indolines, tetrahydroquinolines, dihydroquinazolinones and quinazolinones in high yields. It is also effective for aziridination of alkenes with arylamines as nitrene source. Besides oxidative C-N formation, the iron porphyrin [Fe(2,6-Cl2TPP)OTf] can catalyze tandem epoxidation–isomerization (E–I) of terminal alkenes with PhIO as oxidant to give aldehydes in moderate to high yields [4]. Many of these catalytic reactions feature high regio- and diastereoselectivity and/or high product yields and substrate conversions, demonstrating the applicability of iron porphyrin-catalyzed oxidative organic transformation reactions in practical organic synthesis.