Elucidation of selectivity Difference in the Diels-Alder Reactions of 6,6-Disubstituted Cyclohexa-2,4-dienone

Bulletin of the Korean chemical society

Oh-Seuk Lee¹  Jun-Pyeong Jeong¹  Kiyull Yang¹ 

关键词: Cycloaddition;    Diels-Alder reaction;    Cyclohexa-2;    4-dienone;    Semiempirical MO.;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

Recently it was reported that cycloaddition of 6,6-disubstituted cyclohexa-2,4-dienone, 1 with cyclopentadiene gave solely the adduct of type �?, while its reaction with 1,3-cyclohexadiene gave both ケand �?. Semiempirical MO calculations were done to elucidate the origin of theselectivity difference between the two dienes. Cycloaddition of 1 with cyclopentadiene is controlled thermodynamically to give only 1-diene adduct by �?G values of 10.6-20.3 kcal/mol, while its reaction with 1,3-cyclohexadiene does not show 1-diene/1-dienophile selectivity due to similar stabilities of the two adducts. Thermodynamic parameters also show that endo adducts are more favourably formed in the cycloadditions of 1 with both cyclopentadiene and 1,3-cyclohexadiene, which coincides with experimental observations. Cope rearrangement of endo adducts are avenue to convert between 1-diene and 1-dienphile.

【 授权许可】

Unknown