A Theoretical Study on the S olvent Eff ects in per icyclic Re actions Part I: ۳,۴-Di methyl-۲, ۵-dihydrothiophen-۱,۱-dioxid e

Cheletro pic reactions were defined by Wood ward and Hoffmann as pericyclic reactions in which two ıbon ds are made or broken in a single atom. Some authors co nsider these reactions to be a sub-class of cycload dition. Experimental work has show n that a Di els-Alderadd uct is the kinetic product of reactions of sulfur dioxide with conjugated dienes but that the adduct is thermally unstable and readily undergoes a retro-Diels-Alder reac tion to ۱,۳-butadiene and sulfur dioxide accordin g to scheme ۱ [۱]. On t he other hand, the analysis of the wa ve functions of the transition structures by means of a theoretical method (HOMO-L UMO analy sis), allows us to throw some light on the stability of the TS through whi ch the retro Diels-Alder reaction proceeds. The next step of our investigat ion inferred the influence of the so lvent on the retro-cheletropicene rea ction in detail from the theoretical point of vi ew, in orde r to examine the pres ence of specific interactio ns between three differ ent solvents and reactant /TS.

کلیدواژه ها:

Solvent effects ، Transition State ، ۳ ، ۴-dimethyl-۲ ، ۵-dihydr othiophen-۱ ، ۱-dioxide