Reaction of dichlorocarbene with sterically protected phosphabutatriene. Formation of a stable dimethylenephosphirane

Toyota, Kozo; Yoshimura, H.; Uesugi, Takuji; Yoshifuji, Masaaki

doi:10.1016/0040-4039(91)80432-6

Cited by 18 publications

(5 citation statements)

References 16 publications

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“…Addition of CCl 2 to the phosphabutatriene 184 leads to the corresponding ethenylidenephosphirane 198 which rearranges on warming to the stable phospha [3]radialene 199 77 according to a radicalar mechanism (eq 66); a similar rearrangement was observed with C,C-dichlorophosphiranes obtained from phosphaallenes (see section II.C.6) (eq 21). This type of isomerization leading to radialenes has also been observed in other ethenylidenephosphiranes 183 and ethenylidenethiiranes 184 (eq 67).…”

Section: Reaction With Dichlorocarbenementioning

confidence: 84%

Heavy Allenes and Cumulenes ECE‘ and ECCE‘ (E = P, As, Si, Ge, Sn; E‘ = C, N, P, As, O, S)

2000

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Section: Reaction With Dichlorocarbenementioning

confidence: 84%

Heavy Allenes and Cumulenes ECE‘ and ECCE‘ (E = P, As, Si, Ge, Sn; E‘ = C, N, P, As, O, S)

2000

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“…Cyclic alkenylidenephosphirane 20A has a strikingly different X-ray crystal structure, particularly with respect to the allenic C(2)C(3)C(4) unit, which is significantly bent at C(3) with an angle of 171.5(7)°, suggesting ring-induced strain. This bending contrasts the near allenic linearity in the acyclic structures 19A (179.1(10)°), episulfide 24 (178.3°), and several cyclopropane derivatives (178.0−179.4°) . Not only is the allene unit in 20A bent, it is also twisted by 14.2(8)°; the dihedral angle between the C(1)C(2)C(3) and C(3)C(4)C(5) planes amounts to 75.8(8)°.…”

Section: Resultsmentioning

confidence: 85%

“…They are shown in Figures and , respectively. Of the heterocyclic systems only a crystal structure of the sulfur analogue 24 has been reported . Selected bond lengths and angles are listed in Table , which also contains crystal structure data for 12 8 and 13 6 and MP2/6-31G* geometrical parameters of 17 , 25 , and C 2 H 5 P ( 16 ).…”

Section: Resultsmentioning

confidence: 99%

Phospha[3]radialenes. Syntheses, Structures, Strain Energies, and Reactions

et al. 2000

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In situ-generated terminal phosphinidene complex PhPW(CO) 5 adds in a 1,2-fashion to the terminal double bond of tetramethylcumulene and cyclic 1,2,3-cyclodecatriene. The resulting alkenylidenephosphiranes 19A and 20A, which are three-membered phosphiranes containing an exocyclic allenic group, subsequently rearrange to the corresponding phospha[3]radiales 19B and 20B, which are phosphiranes having two exocyclic double bonds. All four organophosphorus compounds were characterized by single-crystal X-ray structure determinations. Bicyclic 20A contains a significantly bent (171.5(7)°) and twisted (14.2(8)°) allenic unit in contrast to 19A. The rearrangement to the thermodynamically favored radialenes is considered to occur by a phosphirane ring opening/closure sequence. On using a second equivalent of PhPW(CO) 5 , insertion takes place into a PC bond of 20B, but not of 19B, to give two new phospha[4]radialene isomers, viz. cis-20C and trans-20C, both of which were characterized by crystal structure determinations. The PPCC ring in these systems is significantly puckered (∼150°), causing the olefinic bonds of the butadiene unit to be much twisted from planarity. Both phospha[3]radialenes undergo Diels-Alder reactions with methyl-1,2,4-triazole-3,5-dione (MTAD), resulting in the case of the acyclic cumulene in the expected addition product 19D of which the phosphirane ring easily hydrolyzes. Cycloaddition of MTAD to 20B does not occur at the radialene's diene unit but rather invokes one of its PC bonds, possibly in a concerted [(σ 2 + π 2 ) + π 2 ] mechanism, to give the unexpected adduct 20F. Ab initio theoretical studies on the parent systems, using the G3(MP2) method, show phospha[3]radialene to be 3.6 kcal/mol more stable than ethenylidenephosphirane. Their strain energies (SE) are calculated to be 32.3 and 29.7 kcal/mol, respectively. The 22.2 kcal/mol SE of phosphirane increases by 5.9 kcal/mol on introducing one exocyclic double bond and by another 4.2 kcal/mol on introducing the second one. Still, the SE of phospha[3]radialene is less than the 39.0 kcal/mol of the more condensed phosphirene.

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“…Likewise, there are only two reports on the more strained phospha[3]radialenes. Yoshifuji et al 15 employed again the CCl 2 carbene addition to phosphabutatriene followed by a rearrangement to give 10, while Maercker and Brieden 16 used a condensation reaction to synthesize 11 from dichlorophosphines and 3,4-dilithio-2,5-dimethyl-2,4-hexadiene.…”

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confidence: 99%

“…Likewise, there are only two reports on the more strained phospha[3]radialenes. Yoshifuji et al used a condensation reaction to synthesize 11 from dichlorophosphines and 3,4-dilithio-2,5-dimethyl-2,4-hexadiene.…”

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confidence: 99%

2-Alkylidenephosphiranes

et al. 1997

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Three stable alkylidenephosphiranes have been synthesized from the addition of the terminal phosphinidene complex Ph-P-W(CO) 5 to allene, 1,1-dimethylallene, and tetramethylallene. Isopropylidenephosphirane 16b was characterized by a single-crystal X-ray structure determination. Demetalation of its W(CO) 5 group provides the uncomplexed compound. The addition reaction with tetramethylallene also yields vinylphosphirane epimers, which rearrange to phospholene 20. Ab initio MP2/6-31G* structures and energies are presented for the parent uncomplexed methylenephosphirane and its dimethyl derivatives.Ring strain augmented by the presence of an exocyclic double bond makes the heteroatom analogues of methylenecyclopropanes (1) fascinating compounds. 1,2 Strain underlies, for example, the biradical interconversion of the valence isomers 2 and 3, which consequently have received particular attention. [3][4][5] While synthesizing such systems is inherently challenging, their presence as reactive and versatile intermediates has been well established. Expectantly, the stability of the methylene derivatives of the aziridines, oxiranes, and thiiranes increases with bulky substituents on the heteroatom, ring, and/or double bond. These sterically congested systems are typically generated via ring closure reactions, either thermally or photochemically induced, rather then by, e.g., the epoxidation of or the nitrene addition to allenes. 1,6 Our interest in these heterocycles and their even more strained higher homologues, the radialenes 4, 7 arose because of the noticeable elusive phosphorus analogues. 8Only recently did Yoshifuji et al. 9 report the first synthesis of a congested methylenephosphirane, 5, via the addition of dichlorocarbene to a sterically protected 1-phosphaallene (eq 1). No structural details were provided. Subsequently, Manz and Maas 10 reported two similarly congested methylenephosphiranes 6a,b. These stable compounds were obtained from thermal N 2 -extrusion of diazaphosphole precursors, thereby extending the method explored in detail by Quast and coworkers 11 for the syntheses of the O-, S-, and N-analogues. Product formation is presumed to occur via ring closure of the reactive 2-phosphacumulene intermediates (eq 2). The yields are modest due to competing biradical H-abstractions. The difference between the ab initio geometry of the parent methylenephosphirane, C 3 H 5 P (7), 12 and the single-crystal X-ray structure of 6a emphasizes the effect of steric crowding (see also later). 10 These two synthetic routes are, however, rather limited in scope due to the high sensitivity of phosphaallene and 2-phosphacumulenes. 8 A third route has been attempted, Penn, R. E.; Ennis, M. D.; Owens, T. A.; Yu, S. L. J. Am. Chem. Soc. 1978, 100, 7436. Jongejan, E.; Buys, Th. S. V.; Steinberg, H.; de Boer, Th. Behr, H.; Adiwidjaja, G.; Tangerman, A.; Lammerink, B. H. M.; Zwanenburg, B.

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Reaction of dichlorocarbene with sterically protected phosphabutatriene. Formation of a stable dimethylenephosphirane

Cited by 18 publications

References 16 publications

Heavy Allenes and Cumulenes ECE‘ and ECCE‘ (E = P, As, Si, Ge, Sn; E‘ = C, N, P, As, O, S)

Heavy Allenes and Cumulenes ECE‘ and ECCE‘ (E = P, As, Si, Ge, Sn; E‘ = C, N, P, As, O, S)

Phospha[3]radialenes. Syntheses, Structures, Strain Energies, and Reactions

2-Alkylidenephosphiranes

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