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Titolo:
On the behavior of alpha,beta-unsaturated thioaldehydes and thioketones inthe Diels-Alder reaction
Autore:
Li, GM; Niu, S; Segi, M; Tanaka, K; Nakajima, T; Zingaro, RA; Reibenspies, JH; Hall, MB;
Indirizzi:
Texas A&M Univ, Dept Chem, College Stn, TX 77843 USA Texas A&M Univ College Stn TX USA 77843 t Chem, College Stn, TX 77843 USA Kanazawa Univ, Fac Engn, Dept Chem & Chem Engn, Kanazawa, Ishikawa 9208667, Japan Kanazawa Univ Kanazawa Ishikawa Japan 9208667 wa, Ishikawa 9208667, Japan
Titolo Testata:
JOURNAL OF ORGANIC CHEMISTRY
fascicolo: 20, volume: 65, anno: 2000,
pagine: 6601 - 6612
SICI:
0022-3263(20001006)65:20<6601:OTBOAT>2.0.ZU;2-V
Fonte:
ISI
Lingua:
ENG
Soggetto:
MOLECULAR-ORBITAL METHODS; BASIS SET; CHEMISTRY; SELENOALDEHYDES; TELLUROAMIDES; THIOACROLEIN; SELENOAMIDES; DERIVATIVES; OLEFINS; DIMERS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
53
Recensione:
Indirizzi per estratti:
Indirizzo: Li, GM Tokiwa Corp, Cosmet Div, Dept Res & Dev, Adachi Ku, 1-8-11 Shinden,Tokyo 1230865, Japan Tokiwa Corp 1-8-11 Shinden Tokyo Japan 1230865 okyo 1230865, Japan
Citazione:
G.M. Li et al., "On the behavior of alpha,beta-unsaturated thioaldehydes and thioketones inthe Diels-Alder reaction", J ORG CHEM, 65(20), 2000, pp. 6601-6612

Abstract

alpha,beta-Unsaturated thioaldehydes and thioketones, R1CH=CH-C(=S)R-2, are prepared in situ by the reaction between the corresponding carbonyl compounds and bis(dimethylaluminum) sulfide. These compounds undergo [4 + 2] self-dimerization reactions in which one molecule serves as the heterodiene component and the other as the dienophile to afford different types of dimeric products depending on the R-1 and R-2: 1,2-dithiin and 1,3-dithiin (R-1 =R-2 = H), 1,2-dithiin (R-1 = Ph, R-2 = H, CH3), or dihydrothiopyran (R-1 =R-2 = Ph). These differences in selectivity are explained on the basis of the relative energies evaluated by molecular orbital (MO) calculations at the DFT (density functional theory) level. The calculations show that in thedimerization reaction of thioacrolein (I) the head-to-tail (S-C-S bonded) dimers are kinetically more stable by about 5 kcal/mol but slightly thermodynamically unstable by about 2 kcal/mol than the head-to-head (S-S bonded) dimers. The calculations on thiocinnamaldehyde (IV) indicate that the dimerization reactions of phenyl-substituted a,e-unsaturated thioaldehydes and thioketones are almost equally controlled by thermodynamic and kinetic factors. These unsaturated thiocarbonyl compounds also function as heterodienes (C=C-C=S) in the cycloaddition reaction with norbornadiene and as dienophiles (C=S) in the reaction with cyclopentadiene.

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Documento generato il 19/09/20 alle ore 14:20:44