3-((λ3-Oxidanylidene)(propylamino)methyl)-2-ethoxybenzo[e]-[1,2]oxaphosphinine-2-oxide

A method for the simple preparation of 2-ethoxy-N-propylbenzo[e][1,2]oxaphosphinine-3-carboxamide 2-oxide via an ultrasound technique using catalytic amounts of CuI is reported. The formation of the amide could indicate the isomerization of the formed E-alkene intermediate to its Z-form, assisted by the sonication irradiation, and such transformation under the presented conditions has not been previously reported in the literature.