Phosphirane oxide

Typically the C-P-C intracyclic angle of phosphirane and its uncomplexed derivatives amounts mostly in the range of 46-47°. The C-P bond lengths range from 1.830 to 1.886 A whereas the C-C bonds vary from 1.488 to 1.466 A, reflecting the influence of the substitution pattern. Worthy of mention is that the complexed phosphirane has an explicitly lengthened C-C bond length in comparison to the uncomplexed phosphirane, which is also true in the case of the phosphirane oxide. The same tendency is determined in the phosphirene case. 

In the chemistry of the heavier analogues of phosphiranes, no significant new features have been reported since CHEC-II(1996). Worthy of mention is a theoretical study of the rearrangement of arsirane oxides to As-hydroxy arsiranes in analogy to the rearrangement of phosphirane oxides see Scheme 3 and <2000JOC8574>. 

This approach was initially developed by Quast and Henschmann <78AG(E)867,81LA977) for the synthesis of the first stable, sterically hindered, phosphirane oxide (29) (Equation (69)). 

Subsequently, Oshikawa and Yamashita <86BCJ3293> reported a similar chemistry (Equation (70)). Curiously, the stereochemistries of these two phosphirane oxides are different. ... 

By use of a similar method other more stable 1-substituted phosphiranes are prepared, 1-phenylphosphirane (123) being the most stable. When the cyclooctatetraene dianion is treated with dichlorophenylphosphine the bicyclic 1-phenylphosphirane derivative (124) is formed. At 70 °C in CHC13 it rearranges into the bicyclic phosphabicyclo[4.2.1]heptane derivative (125). Oxidation and photochemical reaction give the tricyclic phospholene 1-oxide derivative (126 equation (76)) (66JA3832). 

Whereas the oxidation and quaternization of e.g. (122) give unstable phosphirane 1-oxides or phosphiranium ions, other syntheses with ring substituted phosphiranes give stable derivatives with P-CiV = 4. Quast prepared 1,2,3-tri-f-butylphosphirane 1-oxide (129) by... 

The bulky silylphosphide lib was allowed to react with styrene oxide to give the corresponding trans- and c/s-phosphiranes (equation 95)120. 

Durch Metallierung mit 1-Methyl-propyl-lithium und Umsatz mit Tetrachlormethan laBt sich Bis-[2,2-dimethyl-propyl)-tert.-butyl-phosphanoxid zu tert.-Butyl-(l-chlor-2,2-di-methyl-propyl)-(2,2-dimethyl-propyl)-phosphanoxid umsetzen, das mit Lithiumdiethyl-amidzu l,2,3-Tri-tert.-butyl-phosphiran-l-oxid (52%, Zers.-p. 119—120°) cyclisiert409 ... 

Starting from the phosphinidene complex (22) and ketones, the double-bond metathesis reaction provides access to a phosphaalkene and the zirconocene oxide (Cp2ZrO) . A similar situation is also observed in the reaction with epoxides to give the corresponding phosphiranes (Scheme 6). ... 

The first splitting of a phosphirane derivative into an alkene and a phosphinidene fragment was described by Quast and Heuschmann <82CB90i>, and involved an oxide (29) (Scheme 11). The retention of the stereochemistry of the alkenic fragment suggests a concerted mechanism. A clean thermal splitting has also been observed for several phosphirane complexes (Schemes 12 and 13)... 

The three-fold co-ordination of phosphorus(v) in compound (47) has been confirmed by a full X-ray structure important parameters are included with the formula, but noteworthy is the shortness of the P—N(imine) bond, in agreement with the presence of (p-p)ir interaction. Compound (47) is known to be the oxidation product of the phosphorus(m) compound (44) with trimethyl-silylazide, but when diazomethane is used the ylide analogue (Me3Si)2-NP(=NSiMe3)(=CH2) cannot be isolated, and the product is the phosphiran (48) formed by a 1,2-cycloaddition.A similar process occurs between diazomethane and (47), when the novel azaphospiridine (49) results. 

The reaction of the lithium phosphide 7 with styrene oxide eliminates siloxide to give an isomeric mixture of phosphiranes dominated by the E-isomer (equation 16)24. 

The alkylation of anions derived from 78 with styrene oxide afforded the diastereomeric mixture of 79 through a phospha-Wittig reaction with very little asymmetric induction from the menthyl group. In these reactions, complete inversion of configuration of the stereogenic oxirane carbon was observed. The individual diastereomers of 79 could be separated by column chromatography or recrystallisation. Decomplexation with dppe furnished the free enantiopure phosphiranes, which were complexed to Rh. ... 

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