Phosphiranes, synthesis

Phosphetanium tetrachloroaluminum salt, 1-chloro-2,2,3-trimethyl-1-phenyl-synthesis, 1, 524 Phosphindole synthesis, 1, 517 Phosphine, pyrazol-l-yl-synthesis, 5, 236 Phosphirane, 1-phenyl-synthesis, 1, 525 Phosphirane, 1,2,3-tri-t-butyl-... 

Borst et al. <2005CEJ3631> conducted a study on the synthesis of strained bicyclic phosphirane and phosphirene iron-tetracarbonyl complexes (Scheme 11). It was shown that, depending on the ring size of the resulting heterocycle, electrophilic phosphinidene [Ri-PrNP=Fe(CO)4] could be trapped intramolecularly with both double and triple bonds (compounds 146-150). The phosphinidene addition was found to be reversible at room temperature and when using phenylacetylene as solvent, exchange between phenylacetylene and the phosphinidene group took place. Compound 151 was isolated as the dimer, compound 152. 

Yet another synthesis of a phosphirane derivative (P-CiV = 4) involves diazomethane addition to (132 equation (79)) (75AG(E)363). 

The availability of phosphaalkenes and phosphaalkynes has led to a further route for the synthesis of phosphiranes and phosphirenes by the formal addition of carbenes or carbenoides to P-C multiple bonds. An example already depicted in Scheme 6 involved in the [2+1] cycloaddition reaction of a stable phosphinotrimethylsilylcarbene to tert-butylphosphaalkyne <1995JA10785, 1999CEJ274>. A carbenoid was also used in the synthesis of an unusual phosphirene from a siloxy-substituted phosphaalkene (Equation 30) <1997JOM(529)127>. 

As shown in Equation (28), the synthesis of phosphiranes involves an intermediate secondary 2-chloroalkylphosphine. A preformed phosphine unit with a leaving group in the /3-position is thus a potential phosphirane precursor <1998HAC607>. This technique was optimized and used for the synthesis of chiral phosphiranes from optically pure 1,2-diols <1996JOC7702>. 

As is obvious from Scheme 17, thermal cyclization of bis-ylides like 44 can lead to the synthesis of phosphiranes or with appropriate substituted ylides to phosphirenes (Equation 31) <1995AGE1849, 1999JA5953, 20020M4919>. 

The chemistry of phosphiranes and phosphirenes and their derivatives comprehends theoretical questions, for example, antiaromaticity of phosphirenes, a -aromaticity, reaction behavior like ring opening of vinylphosphiranes, complex building ability, and synthesis strategies. The cycloaddition reactions of transient phosphinidene metal complexes play an outstanding role. 

Several reports have appeared of the application of unusual organometallic reagents in phosphine synthesis. Treatment of 2-lithiopyridine with anhydrous zinc chloride results in the formation of a 2-pyridylzinc reagent which can be used to introduce the 2-pyridyl group at phosphorus in a controlled manner. Thus, e.g., in its reaction with phenyldichlorophosphine, the 2-pyridyl-(phenyl)chlorophosphine (15) is formed. This has then been converted via the phosphide route into a new class of binucleating ligands (16). The sterically crowded dichlorophosphine (17) (accessible from the reaction of phosphorus trichloride with lithium diphenyl(2-pyridyl)methanide) is converted into the thermally stable phosphirane (18) on treatment with calcium, strontium or barium cyclooctatetraenide.The reaction of phenyldichlorophosphine with the readily accessible titanacycle (19) affords a convenient route to the phosphetene (20). ... 

X -systems, and other low coordination phosphorus species, in particular phosphenium ions, R2P , and phosphinidenes, RP . The reactions of phosphenium ions with isocyanides, 1,3-dienes and o-quinones, and amidines, have been investigated. The coordination chemistry of phosphenium ions also continues to stimulate interest.The thermal decomposition of phosphirene and phosphirane P-complexes provides a new approach for the synthesis of terminal phosphinidene complexes, e.g., (180), which can be trapped with a variety of reagents. Evidence of the formation of surface phosphinidene intermediates has been adduced in the heterogeneous dechlorination of alkyldi-chlorophosphines by magnesium metal at 600K. ... 

SYNTHESES OF PHOSPHIRANES AND PHOSPHIRENES 1.08.4.1 Synthesis from P and C2 Units... 

It has been shown that oxiranes can replace 1,2-dihaloalkanes in the synthesis of phosphiranes, provided that appropriate anionic RP reagents are used. The first example was described by Yoshifuji et al. (Equation (54)) <85CL44l>. Subsequently, it has been shown by Marinetti et al. that the so-called phospha-Wittig reagents transform oxiranes into phosphiranes with an inversion of configuration at carbon (Scheme 19) <92Sl57,93OM1207). Decomplexation by 1,2-bis(diphenylphos-phino)ethane is easily achieved in the molybdenum series. Optically active phosphiranes are readily accessible by this route. 

The use of the second approach is restricted by the availability of 1,2-dimetallic derivatives of alkanes. The first example of a synthesis of 2-vinyl-substituted phosphiranes was described by Richter, using the magnesium-butadiene polymeric adduct (Equation (55)) <82AG(E)292, 83CB3293). A second example concerning the synthesis of phospha[3]radialenes has also been disclosed (Equation (56)) <91CB933>. The allenyl-substituted phosphiranes isomerise into phospha[3]radialenes upon distillation at standard pressure. 

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)). 

The first specific synthesis of a polycyclic phosphirane was depicted by Katz et al. in 1966 <66JA3832, 73JA4292), soon after the discovery of phosphirane itself by Wagner. It involves the reaction of cyclooctatetraene dianion with dihalophosphines (Equation (73)) <66JA3832, 82TL4915, 85CB97, 89CC973). 

The first monocyclic arsirane was prepared by Appel et al. <85AG(E)419) by a transposition of the synthesis of phosphiranes from bis-ylides (Scheme 34). The structure of this arsirane has been established by x-ray analysis As—C ring bond 2.023 A, C—C ring bond 1.581 A, intracyclic C—As—C angle 46.0°, exocyclic (Ph)C—As—C angle 111.8°. No chemistry has been described. 

A new approach to the synthesis of 1-chlorophosphirenes is afforded by the reaction of the phosphirane complex (309), presumably acting as a source of a phosphinidene, with disubstituted alkynes to give the complexed P-aminophos-phirenes (310), which, on treatment with hydrogen chloride, are converted to the related complexed 1-chlorophosphirenes (311). A key step is their selective... 

This results in the formation of complexes of phosphiranes and phosphirenes, respectively, which can be decomplexed to give the free phosphines. Phosphirenes were synthesized for the first time by this technique. A one-pot synthesis of phosphirene complexes from a 3,4-dimethyl-1-phenyl-phosphole complex with tungsten has even been developed <85JA4700>. These applications based on phosphole chemistry are included in a review of the three-membered ring systems <87AG(E)275>. 

Cairns Wagner Existence of circular DNA first demonstrated in bacteria Synthesis of phosphiranes... 

Phosphide anions are excellent nucleophiles and are very reactive to alkylating agents and metal-lophosphine derivatives are of importance as phosphide transfer agents. Lithium diphenyl phosphine can be used to prepare water-soluble phosphines. Dilithium phenyl phosphine can be used in the synthesis of phosphiranes, phosphetanes and so forth (Chapter 6). Lithium bis(trimethylsilyl)phos-phanide, LiP(SiMe3)2, is useful for the synthesis of compounds with P-Si linkages (Figure 9.11). 

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