Cetyltrimethyl ammonium bromide catalysed oxidative cross dehydrogenative coupling of benzylic C(sp3)–H bonds in methylarenes with P(O)–OH compounds?

Organic & Biomolecular Chemistry Pub Date: 2018-12-13 DOI: 10.1039/C8OB02772B

Abstract

An efficient metal-free method for the synthesis of organophosphorus compounds via oxidative cross dehydrogenative coupling of benzylic C(sp3)–H bonds in methylarenes with P(O)–OH compounds catalysed by cetyltrimethyl ammonium bromide (CTAB) is reported. Various methylarenes and P(O)–OH compounds are tolerated in the reaction with moderate to good yields. Compared to previous studies, the present study extends the substrate scope and adopts a new reaction system of an ammonium salt catalyst (CTAB) and an oxidant (DTBP). The results of control and mechanistic experiments are generally in agreement with the overall proposed pathway. This method circumvents the use of toxic P–halogen reagents and P(O)–H compounds for the synthesis of organophosphorus compounds.

Graphical abstract: Cetyltrimethyl ammonium bromide catalysed oxidative cross dehydrogenative coupling of benzylic C(sp3)–H bonds in methylarenes with P(O)–OH compounds
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