A Primary Acyl Phosphine Stabilized by a Phosphonium Ylide

Abstract Primary acyl‐phosphines are scarce in the literature. Here we show that the reaction of Ph 3 GePCO with the ylide Ph 3 PCH 2 proceeds to give the species Ph 3 PCHC(O)PH(GePh 3 ) 1 . Deprotonation of 1 with Na[N(SiMe 3 ) 2 ] generates the salt [Na(THF) 2 ][Ph 3 PCHC(O)P(GePh 3 )] 2 which provides subsequent access to the bis ‐germanylated acylphosphine, Ph 3 PCHC(O)P(GePh 3 ) 2 3 . Alternatively, treatment of 1 with HCl in dioxane affords the primary acylphosphine Ph 3 PCHC(O)PH 2 4 . Compound 4 is a rare example of an air stable primary acyl‐phosphines and the first devoid of a stabilizing heteroatom adjacent to the carbonyl fragment.