.alpha.-Halo sulfones. XIV. [4.4.2]Propella-2,4,7,9,11-pentaene

Paquette, Leo A.; Philips, J. Christopher

doi:10.1021/ja01042a063

Cited by 11 publications

(10 citation statements)

References 2 publications

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“…Caled for C9Hi3NO: C, 71.49; H, 8.67; N, 9.26. Found: C,71.78;H,8.57;N,non-7-ene (5). A mixture of 275 mg (2.0 mmol) of 2 and 324 mg (2.18 mmol) of trimethyloxonium fiuoroborate in 3 ml of dry methylene chloride was stirred under nitrogen at ambient temperature for 1 hr and then under gentle reflux for 1 hr.…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, when a uniparticulate electrophile, a reagent incapable of fragmentation, is allowed to react with an olefin, a cyclic product generally results. 5 Geometric constraints, when applicable, are recognized to play a major role in determining the structure of the addition product.6 Additionally, such reagents constitute unusually effective probes for use in examining competitive rate situations7 and in trapping transient carbonium ions which could otherwise pass undetected.8,9 Their capability to accom- (1) Senior Education Awardee, American Cyanamid Co., 1969Co., -1970 NATO Postdoctoral Fellow, 1970-1972 (3) For an extensive survey, see P. B. D. de la Mare and R. Bolton, "Electrophilic Additions to Unsaturated Systems," Elsevier Publishing Co., New York, N. Y., 1966. (4) W. R. Dolbier, Jr., J.…”

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confidence: 99%

“…Educ., 46, 342 (1969). (5) The stereospecific addition of chlorosulfonyl isocyanate to cis and trans alkenes is exemplary: (a) E. J. Moriconi and J. F. Kelly, Tetrahedron Lett., 1435 (1968); (b) H. Bestian, H. Biener, K. Clauss, and H. Heyn, Justus Liebigs Ann. Chem., 718, 94 (1968)…”

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confidence: 99%

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Addition reactions of the uniparticulate electrophile chlorosulfonyl isocyanate to highly strained bicyclic hydrocarbons

Paquette¹,

Allen²,

Broadhurst³

1971

J. Am. Chem. Soc.

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Section: Methodsmentioning

confidence: 99%

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confidence: 99%

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Addition reactions of the uniparticulate electrophile chlorosulfonyl isocyanate to highly strained bicyclic hydrocarbons

Paquette¹,

Allen²,

Broadhurst³

1971

J. Am. Chem. Soc.

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“…Cyclooctatetraenes 20 and 21 have been isolated earlier from thermal isomerization of the respective propellatrienes in the gas phase at 430-485 0C.3•5 The purely thermal process proceeds by an intramolecular Diels-Alder reaction, cleavage of two strained cyclopropane bonds in the resulting bishomobenzene intermediate, and ultimate valence tautomerism to deliver product. Incursion of a second symmetry-allowed process, the [1,5] sigmatropic carbon shift, is not observed.…”

Section: Resultsmentioning

confidence: 81%

“…The above data reveal that the thermal and metal-catalyzed rearrangement of the [4.4.2]propella-2,4,11-trienes proceed along entirely different mechanistic channels. Further, some mode of [1,5] sigmatropic shifting of a trigonal cyclobutene carbon appears to be implicated when the molybdenum catalyst is present. If this is so, then monoalkyl substitution of the cyclobutene ring should lead to large differences in the migratory aptitudes of Cu and C12.…”

Section: Resultsmentioning

confidence: 99%

Binding of unsaturated propellanes to transition metal centers, hexacarbonylmolybdenum-promoted skeletal isomerization of [4.4.2]propella-2,4,11-trienes

Paquette¹,

Photis²,

Micheli³

1977

J. Am. Chem. Soc.

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The R amberg‐ B äcklund Rearrangement

Paquette

1977

Organic Reactions

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The halogen atoms of α‐halo sulfones, in contrast to halogen atoms α to other electron‐withdrawing functionalities, show marked resistance to substitution by external nucleophiles. Seemingly, polar, steric, and field effects combine to repel nucleophilic species. However, the same α‐sulfonyl halogen atoms are capable of facile intramolecular 1,3 elimination, leading to replacement of the sulfonyl group by a carboncarbon double bond with loss of halide and sulfite ions. This extrusion process, frequently referred to as the α‐halo sulfone or Ramberg‐Bäcklund rearrangement after its discoverers, has found broad utility in olefin synthesis. The reaction is generally applicable and easy to use. Its earliest application dealt with the preparation of alkenes, the cis isomers of which predominated. Whereas such molecules may be more readily available by other methods, none of the alternative procedures offers the added option of specifically replacing the olefinic hydrogen atoms with deuterium by merely conducting the rearrangement in deuterated solvents. Moreover, because the α‐halo sulfones undergo this transformation in alkaline solution, further rearrangement of the initially formed alkenes is precluded. Therefore the SO 2 group in the starting sulfone is invariably replaced cleanly and unequivocally by the π bond. The rearrangement is generally applicable to molecules containing the minimal structural requirements of a sulfonyl group, an α‐halogen atom, and at least one α′‐hydrogen atom, even in systems leading to small‐ring cycloalkenes. Di‐ and tri‐halo sulfones behave analogously. Conformational constraints, adverse hybridization characteristics, and excessive strain are known to deter the reaction. Inasmuch as these features arise only in special circumstances, they do not necessarily detract from its usefulness. This chapter summarizes the more important advances in the understanding of α‐halo sulfone rearrangements, particular consideration being given to the nature of the intermediates, scope of the available synthetic alternatives, optimization of experimental conditions, and effect of structural features on reactivity. Closely related transformations are also discussed.

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.alpha.-Halo sulfones. XIV. [4.4.2]Propella-2,4,7,9,11-pentaene

Cited by 11 publications

References 2 publications

Addition reactions of the uniparticulate electrophile chlorosulfonyl isocyanate to highly strained bicyclic hydrocarbons

Addition reactions of the uniparticulate electrophile chlorosulfonyl isocyanate to highly strained bicyclic hydrocarbons

Binding of unsaturated propellanes to transition metal centers, hexacarbonylmolybdenum-promoted skeletal isomerization of [4.4.2]propella-2,4,11-trienes

The R amberg‐ B äcklund Rearrangement

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