Hetero-Diels-Alder and Cheletropic Additions of Sulfur Dioxide to 1,2-Dimethylidenecycloalkanes. Determination of Thermochemical and Kinetics Parameters for Reactions in Solution and Comparison with Estimates From Quantum Calculations
作者:Frédéric Monnat、Pierre Vogel、José Ángel Sordo
DOI:10.1002/1522-2675(200203)85:3<712::aid-hlca712>3.0.co;2-5
日期:2002.3
collected for these reactions. The sultines are ca. 10 kcal/mol Diels-Alder additions (DeltaH(+)(16 + SO2 --> 19) = 6.6 +/- 0.2 kcal mol(-1) and DeltaH(+)(13 + SO2 --> 14) = 7.2 +/- 0.4 kcal mol(-1)) are ca. 2 kcal smaller than the activation enthalpies of the corresponding cheletropic additions. The activation entropies of the hetero-Diels-Alder additions (DeltaS(+)(16 + SO2 --> 19) = -50.3 +/- 1.1 cal mol(-1)
在 -60 以下且没有催化剂的情况下,1,2-二甲基环戊烷 (16)、1,2-二甲基环己烷 (13)、1,2-二甲基环庚烷 (17) 和 1,2-二甲基环辛烷 (18) 添加到杂二硫化物中的二氧化硫-Alder 模式,得到相应的 sultines 4,5,6,7-tetrahydro-1H-cyclopent[d][1,2]oxathiin 3-oxide (19), 1.4.5,6,7,8-hexahydro-2 ,3-benzoxathiin 3-oxide (14), 4,5,6,7,8,9-hexahydro-1H-cyclohept[d][1,2]oxathiin 3-oxide (20), 和 1,4,5 ,6,7,8,9,10-octahydrocyclooct[d][1,2]oxathin 3-oxide (21)。在-40度以上,sultines异构化成相应的环丁砜3,4