Synthesis of [2-(methoxyaryl)-1-methylethyl]phosphinic acids from red phosphorus and (allyl)(methoxy)benzenes

Abstract

(Allyl)(methoxy)benzenes react with red phosphorus in the superbasic system KOH-DMSO in the presence of small amounts of water and hydroquinone (3 h, 130 °C) to regio- and chemoselectively give [2-(methoxyaryl)-1-methylethyl]phosphinic acids in preparative yields up to 52%. The reactions involve isomerization of allylbenzenes into (prop-1-enyl)benzenes.