1,3,2-Diazaphosphinines and -Diazaarsinines as Precursors for Polyfunctional Phosphinines and Arsinines

Abstract

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Recent Developments in the Chemistry of N-Heterocyclic Phosphines

“…Fully unsaturated 1,3,2-diazaphosphinines are readily prepared in fair yields of 40-45% in a one-pot reaction from Cp 2 TiMe 2 (Scheme 16 ) [84,85] . The starting material is first reacted with pivalonitrile or benzonitrile to give 1,3,2-diazatitanacyclohexadienes which are then quenched by subsequent addition of phosphorus trichloride followed by triethylamine.…”

“…The heterocycles 27 are highly air and moisture sensitive and are usually directly employed for subsequent reactions; however, the 4,6-di-tert -butylderivative has also been isolated as crude product in 40% yield after a simple workup procedure involving filtration of insoluble products and evaporation of volatiles, and has been characterized by multinuclear NMR data. It has been pointed out that this compound seems to be preferable as starting material for further synthetic transformations as it is more readily separated from unreacted nitrile and is slightly more stable than the phenylated derivative as the bulkier substituents offer superior steric protection [85] . Neutral 2,3-dihydro-1,3,2-diazaphosphinines are straightforwardly accessible from condensation of 4-amino-1-azabutadienes with appropriately substituted dichlorophosphines or PCl 3 (Scheme 16 ).…”

“…1,2-Dihydrol,3,2-diazaphosphinines react via a unique [5 + 2] cycloaddition to dimethyl acetylenedicarboxylate to furnish bicyclic iminophosphoranes which may subsequently undergo further rearrangement to yield isomeric ylides [87,95] . The significance of 1,3,2-diazaphosphinines lies in their use to react with alkynes under formation of phosphinines [84,85] . The transformation is like the 1,3,2-diazaphosphole/ 1,2-azaphosphole transformation [70] 31 P NMR but is usually directly subjected to a second [4 + 2]-cycloaddition/cycloreversion sequence with the same or a different alkyne which furnishes finally the desired phosphinine.…”

A New Mixed P,S‐Bidentate Ligand Featuring a λ4‐Phosphinine Anion and a Phosphanyl Sulfide Group − Synthesis, X‐ray Crystal Structures and Catalytic Properties of Its Chloro(cymene)ruthenium and Allylpalladium Complexes

“…[24,25] This precursor proved to be a very efficient source of tetrafunctionalised phosphinines through successive [4 ϩ 2] cycloaddition/cycloreversion processes with functionalised alkynes. We first focused our work on the synthesis of diphenyl(3-R-5,6-diphenylphosphinin-2-yl)phosphane sulfide derivatives.…”

A 1‐Methyl‐Phosphininium Compound: Synthesis, X‐Ray Crystal Structure, and DFT Calculations

“…Their syntheses rely on the oxidation of anions 3 and 4 that were conventionally produced by treating methyllithium with phosphinines 1 [7] and 2, [8] respectively (Scheme 1). [9] We tried to duplicate the strategy reported by Dimroth and co-workers, and therefore compounds 5 and 6 were treated with AlCl 3 in CH 2 Cl 2 at room temperature.…”