Ethyl 3‐(diphenylphosphinoyl)‐3‐phenylpropionate

The title compound, Ph 2 P(O)CH(Ph)CH 2 COOEt or C 23 H 23 O 3 P, (I), assembles into columns extending down the a axis, via C—H⋯O hydrogen bonds. Compound (I) was isolated as a by‐product in studies related to the development of a novel cyclization reaction [Evans et al. (2002). Tetrahedron Lett. 43 , 299–301] and was synthesized independently to confirm its structure.