Abstract The reaction of triphenylphosphine with some organometal haloacetates [(CH 3) 3 SiOCOCHBr 2,(CH 3) 3 SiOCOCCl 3,(nC 4 H 9) 3 SnOCOCCl 3 and (CH 3) 3 Sb (OCOCCl 3) 2] gave the corresponding organometal halides (ca. 80%) and (C 6 H 5) 3 PO (ca. 90%), and in the presence of cyclopentadiene, cycloaddition products (ca. 30%). Evidence was obtained that the enolphosphonium salt, Full-size image (2 K)