Continuous Flow Esterification of a <i>H</i>-Phosphinic Acid, and Transesterification of <i>H</i>-Phosphinates and <i>H</i>-Phosphonates under Microwave Conditions

Abstract

The microwave (MW)-assisted direct esterification of phenyl-H-phosphinic acid, transesterification of the alkyl phenyl-H-phosphinates so obtained, and the similar reaction of dibenzyl phosphite (DBP) were investigated in detail, and the batch accomplishments were translated into a continuous flow operation that, after optimization of the parameters, such as temperature and flow rate, proved to be more productive. Alcoholysis of DBP is a two-step process involving an intermediate phosphite with two different alkoxy groups. The latter species are of synthetic interest, as precursors for optically active reagents.

Keywords

• <i>h</i>-phosphinic acid
• esterification
• <i>h</i>-phosphinates
• <i>h</i>-phosphonates
• transesterification
• microwave flow reactor