Synthesis and properties of tert-butylphenylmethylene(chloro)phosphorane

Abstract

The synthesis and properties of tert-butylphenylmethylene(chloro)phosphorane were described. The prepared chlorophosphorane reacted with alcohols and phenol with the formation of the corresponding phosphonium salts. Its reaction with carbonyl compounds led to the formation of 2-chloro-1,2λ 5 -oxaphosphetanes, which rearranged providing 2-chloroalkylphosphine oxides or alkenylphosphine oxides.

Synthesis, Properties and Stereochemistry of 2-Halo-1,2λ⁵-oxaphosphetanes

“…The 2-halo-1,2λ 5 -oxaphosphetanes were prepared by reaction of P-fluoro-, chloro-or bromoylides with carbonyl compounds. P-Chloro-and P-bromoylides react with active ketones, containing a trifluoromethyl group, with the formation of stable [2+2]-cycloaddition products, 2-chloro-or 2-bromo-1,2λ 5 oxaphosphetenes 14 were isolated in yields close to quantitative as crystalline substances or as liquids distillable in vacuum (Scheme 8, Table 1) [24][25][26][27][28][29][30][31][32].…”

Synthesis, Properties and Stereochemistry of 2-Halo-1,2λ⁵-oxaphosphetanes

“…Dissociation of 2-halo-1,2λ 5 -oxaphosphetanes is enhanced by reducing the electron-accepting properties of substituents and also by increasing priority solvent. The 2-halo-1,2λ 5 -oxaphosphetanes containing electron-accepting groups at C(4) are distinctly stabler than oxaphosphetanes with alkyl groups in this position [25][26][27].…”

“…Hydrolysis of 2-chloro-and bromooxaphosphetanes led to the formation of 2-hydroxyalkylphosphine oxides 36 ( Table 5). The chlorine atom of 2-сhloro-1,2λ 5 -oxaphosphetanes is easily substituted on methoxy-or phenoxy groups by reaction with methanol or phenol in the presence of triethylamine with formation of 2-alkoxyoxaphosphetanes 37, which at heating were converted into alkenes (Scheme 23, Table 1, entries 14,15) [27,42]. The 2-chloro-1,2λ 5 -oxaphosphetanes not containing electron accepting groups at C-3 are unstable and rearrange easily into 2-cloroalkylphosphonates at temperature below +20 °C.…”

“…The 31 Р-NMR spectra of 2-fluoro-oxaphosphetanes 17 present doublets with 800 Hz 1 JРF constants in the high magnetic field of a NMR spectrum at −8− −37ppm. This corresponds to a pentacoordinate state of compounds 17 [24,[26][27][28][29][30][31]. Tetracoordinated forms of 2-fluoro-oxaphosphetanes 17 were not registered by 19 F-and 31 P-NMR spectroscopy (Scheme 11).…”

“…These compounds are much distinguished from unstable adducts of carbonyl compounds with triphenylphosphonium ylides. Cycloadducts of P-fluoroylides with carbonyl compounds, 2-fluoro-1,2λ 5 -oxaphosphetanes, are also much more stable than 2-chloro-or 2-bromo-1,2λ 5 -oxaphosphetanes [25][26][27][28][29][30][31]. The stability of 2-fluoro-oxaphosphetanes is explained by the high electronegativity of the fluorine atom, compared to the electronegativities of chlorine and bromine.…”