The synthesis of the new bulky vinyllithium reagent (MeIPr=CH)Li, (MeIPr=[(MeCNDipp)2C]; Dipp=2,6‐iPr2C6H3) is reported. This vinyllithium precursor was found to act as a general source of the anionic 2σ, 2π‐electron donor ligand [MeIPr=CH]−. Furthermore, a high‐yielding route to the degradation‐resistant SiII precursor MeIPr⋅SiBr2 is presented. The efficacy of (MeIPr=CH)Li in synthesis was demonstrated by the generation of a complete inorganic divinyltetrelene series (MeIPrCH)2E: (E=Si to Pb). (MeIPrCH)2Si: represents the first two‐coordinate acyclic silylene not bound by heteroatom donors, with dual electrophilic and nucleophilic character at the SiII center noted. Cyclic voltammetry shows this electron‐rich silylene to be a potent reducing agent, rivalling the reducing power of the 19‐electron complex cobaltocene (Cp2Co).

The previously unreported carbene-phosphine adduct (IPr)PCl2N3 [IPr = (HCNDipp)2C:; Dipp = 2,6-iPr2C6H3] was synthesized and used as a synthon toward the elusive dichlorophosphazene monomer unit, [Cl2P=N]. (IPr)PCl2N3 was found to undergo halide and azide abstraction when combined with various electrophiles and its thermolysis yielded the unexpected Staudinger reaction product (IPr=N)PCl2.

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. Scheme 1. Selected reactivity of (a) phosphaketenes of the form RPCO (R = SnR 3 , P(NR 2 ) 2 (b) R = GePh 3 c) present work.

Primary acyl‐phosphines are scarce in the literature. Here we show that the reaction of Ph3GePCO with the ylide Ph3PCH2 proceeds to give the species Ph3PCHC(O)PH(GePh3) 1. Deprotonation of 1 with Na[N(SiMe3)2] generates the salt [Na(THF)2][Ph3PCHC(O)P(GePh3)] 2 which provides subsequent access to the bis‐germanylated acylphosphine, Ph3PCHC(O)P(GePh3)2 3. Alternatively, treatment of 1 with HCl in dioxane affords the primary acylphosphine Ph3PCHC(O)PH2 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.

Efforts to deprotonate the halophosphonium cations [Ph2P(X)Me]+ (X = F, Cl) generated species of the form [Ph2(X)PC(H)PPh2Me][X’]. The derivative where X = O3SCF3, provides access to a methylene phosphonium cation....