Iron phthalocyanine-catalyzed radical phosphinoylazidation of alkenes: A facile synthesis of β-azido-phosphine oxide with a fast azido transfer step

Phosphinoylazidation of alkenes is a direct method to build nitrogen- and phosphorus-containing compounds from feed-stock chemicals. Notwithstanding the advances in other phosphinyl radical related difunctionalization of alkenes, catalytic phosphinoylazidation of alkenes has not yet been reported. Here, we describe the first iron-catalyzed intermolecular phosphinoylazidation of styrenes and unactivated alkenes. The method is practically useful and requires a relatively low loading of catalyst. Mechanistic studies confirmed the radical nature of the reaction and disclosed the unusually low activation energy 4.8 kcal/mol of radical azido group transfer from the azidyl iron(III) phthalocyanine species ((PcFeN3)-N-III) to a benzylic radical. This work may help to clarify the mechanism of iron-catalyzed azidation, inspire other mechanism studies and spur further synthetic applications. (C) 2021, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Automated summary

The study presents the first iron-catalyzed intermolecular phosphinoylazidation of styrenes and unactivated alkenes. The reaction is practical and requires relatively low loading of catalyst, with mechanistic studies confirming the radical nature and unusually low activation energy. This work may contribute to elucidating the mechanism of iron-catalyzed azidation and inspire further studies and applications.