Box–Behnken design for the optimisation of Kabachnik–Fields reaction catalysed by natural kaolinite clay under eco-friendly conditions

Abstract

Natural kaolin has been employed as an efficient, simple, and environmentally friendly catalyst for the synthesis of α-aminophosphonates by a multicomponent condensation reaction in one pot via the Kabachnik–Fields reaction. The optimal conditions obtained for the protocol of this reaction (150 mg kaolin has a diameter of 98 μm in 1 mL solvent at 44 °C) were carried out using the Box–Behnken surface response methodology. The eco-friendly method proceeds with this catalytic system for the synthesis of α-aminophosphonate derivatives. The results show a good performance of this clay, which essentially depends on the stereoelectronic effects involved.