Synthese de systemes thia-bicyclo(2,2,2) et (3,2,1) octane par addition intramoleculaire du radical thiyle

Surzur, J. M.; Nouguier, R.; Crozet, Maxime D.; Dupuy, C.

doi:10.1016/s0040-4039(01)96773-5

Cited by 12 publications

(5 citation statements)

References 13 publications

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“…However, because of the reversibility of the addition of thiyl radicals onto alkenes, six-membered rings can be formed preferentially over five-membered rings. Surzur and co-workers have extensively studied the cyclization of alkenyl mercaptans, , and they showed that pent-4-enylthiyl radical 43 , generated from the sulfide 42 upon UV-light irradiation, cyclized to give a mixture of both five- and six-membered rings, with the six-membered rings being formed preferentially (Scheme , eq a). , The formation of a mixture of compounds resulting from 5- exo -trig and 6- endo -trig cyclization processes has been attributed to the reversibility of the addition step. On the other hand, highly regioselective processes have also been observed for the formation of thia-6-bicyclo[3.2.1]octane (Scheme , eq b) .…”

Section: Addition Of Thiols To Cc Bondsmentioning

confidence: 99%

Thiyl Radicals in Organic Synthesis

et al. 2014

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Section: Addition Of Thiols To Cc Bondsmentioning

confidence: 99%

Thiyl Radicals in Organic Synthesis

et al. 2014

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“…The following transformations (280,290) are illustrative of the scope of the reaction: Other N-centered radicals that undergo intramolecular addition include the amidyls (293-294a) e.g., 119 (293) and 120 (294). * Addition of thiyl radicals to olefins is reversible (297 f 298), and it is not surprising, therefore, that ring closure of suitable alkenylthiyl radicals (298)(299)(300)(301)(302)(303)(304)(305), although relatively efficient, lacks regiospecificity. However, for thermodynamic and other reasons, it seems more likely that the observed products arise from the corresponding carboncentered radical 123, which could be formed from the nitroxide 122.…”

Section: E Alkenoxy Alken Aminyi and Other Heteroatom-centered Radimentioning

confidence: 99%

“…Other examples of thiyl radical cyclization include the formation of cyclic compounds containing additional heteroatoms (298,300,301), the formation of bi-and polycyclic systems (302)(303)(304)(305), and the cyclization of acetylenic thiols (306).…”

Section: E Alkenoxy Alken Aminyi and Other Heteroatom-centered Radimentioning

confidence: 99%

Free-Radical Rearrangements

Beckwith¹,

Ingold²

1980

Organic Chemistry: A Series of Monographs

114

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“…As summarized in Table 1, the efficiency and stereospecificity of alkenyl radical cyclizations are fairly distinctive except for two cases, i.e. the cyclizations of carbon radicals substituted with electron-withdrawing groups (13) and thiyl radicals (12). Significantly, reversibility of addition has been demonstrated in these two cases, from which one may conclude that the thermodynamically more stable product is not necessarily the kinetically controlled product.…”

Section: Introductionmentioning

confidence: 97%

“…membered membered membered membered membered membered Reference lar addition of alkoxy (7)(8)(9), amido (10, 1 I), and mercapto (12) radicals. Intramolecular radicalZ addition has been more extensively investigated with alkenyl carbon radicals (13)(14)(15)(16)(17), although other radical cyclizations (7)(8)(9)(10)(11)(12) have begun to attract attention in recent years. As summarized in Table 1, the efficiency and stereospecificity of alkenyl radical cyclizations are fairly distinctive except for two cases, i.e.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of azacyclic compounds by an aminium radical route: orbital overlap requirements

Perry¹,

Chen²,

Menon³

et al. 1976

Can. J. Chem.

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Can. J. Chem. 54, 2385 (1976. Model compounds of A4v5-, A5.'j-, and a6.7-alkenylnitrosarnines were synthesized and photolyzed to generate the corresponding alkenylaminium radicals. The A5~6-alkenylan~inium radicals underwent efficient intramolecular addition leading to the exclusive formation of pyrrolidine derivatives, the yield of which was lower if the steric strain and hindrance were severe in the cyclization transition state. The A6s7-alkenylaminium radical cyclized inefficiently to piperidine derivatives and the A4~5-alkenylarninium radicals did not appear to cyclize; in both cases other pathways having lower activation energies, such as elimination and hydrogen abstraction, predominated. Evidence that the direction of cyclization is controlled by the degree of p-orbital overlap, but not by stability of the developing products, in the transition state is presented. The stereochernical factors associated with the overlap determined the yields of the cyclization products. This is in excellent agreement with the fact that the transition state of cyclization is reached at an early stage in the reaction coordinate. Metal ion catalyzed or radical initiated decomposition of some alkenyl chlorarnines were found either to cyclize to a mixture of pyrrolidine and piperidine derivatives or to undergo no cyclization. Chem. 54, 2385Chem. 54, (1976.On a synthetise et photolyse des cornposCs rnodkles de A4n5-, A5s6-et A6r7-alkenylnitrosarnines qui ont conduit aux radicaux alkknylarninium correspondants. Les radicaux A5:6-alkenylaminium subissent des rkactions d'addition intrarnoliculaires efficaces conduisant a la formation exclusive de derives de la pyrolidine; le rendement de ce compose est diminui si l'emp@chernent et la contrainte stCrique sont importants dans l'etat de transition rnenant a la cyclisation. Le radical A6r7-alkknylarniniurn se cyclise d'une fason inefficace pour conduire a des derives de la piperidine et les radicaux A4.5-alkknylarninium ne sernblent pas se cycliser; dans les deux cas d'autres chernins rkactionels ayant des energies d'activation plus basses, tels que les Climinations et les enlkvernents d'hydrogkne, prkdorninent. On prCsente des donnees indiquant que la direction de la cyclisation est contr6lk par le degrC de recouvrement des orbitales p dans 1'Ctat de transition; il ne semble pas que cette direction soit influenck par la stabilitk des produits qui se forrnent. Les facteurs stCrCochimiques associks avec le recouvrement dkterrninent les rendernents des produits de cyclisation. Ceci est en excellent accord avec le fait que, dans les coordonnees de la reaction, 1'Ctat de transition de la cyclisation est atteint t6t. On a trouvC que les dtkornpositions catalyskes par les ions mCtalliques ou initiies par les radicaux de quelques chloramines d'alkknyles conduisent soit une cyclisation fournissant un mClange de dCrives de la pyrolidine et de la pipkridine soit qu'ils ne conduisent pas des cyclisations.[Traduit par le journal]

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Synthese de systemes thia-bicyclo(2,2,2) et (3,2,1) octane par addition intramoleculaire du radical thiyle

Cited by 12 publications

References 13 publications

Thiyl Radicals in Organic Synthesis

Thiyl Radicals in Organic Synthesis

Free-Radical Rearrangements

Synthesis of azacyclic compounds by an aminium radical route: orbital overlap requirements

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