Reactivity and endo-exo selectivity in Diels-Alder reaction of o-quinodimethanes.: An experimental and DFT computational study

被引:22
作者
Di Valentin, C [1 ]
Freccero, M [1 ]
Sarzi-Amadè, M [1 ]
Zanaletti, R [1 ]
机构
[1] Univ Pavia, Dipartimento Chim Organ, I-27100 Pavia, Italy
关键词
o-quinodimethanes; Diels-Alder reactions; diastereoselection; transition states;
D O I
10.1016/S0040-4020(00)00126-5
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
endo-exo Selectivity in Diels-Alder cycloadditions of several o-quinodimethanes (1-4) with acrylonitrile, 2-(5H)-furanone and N-methylmaleimide has been investigated in acetonitrile solution. Transition structures of the cycloaddition of the parent o-QDM (1), (E,E)1,8-dimethyl-o-QDM (2), isoindene (3) and 2,3-dihydronaphthalene (4) with acrylonitrile and maleimide were located at both HF/6-31G* and B3LYP/6-31G* methods. Theoretical data reproduce fairly well both experimental absolute reaction rates and diastereoisomer ratios. The high endo selectivity has been rationalized mainly as a result of solvation effects (acetonitrile, PCM model) and reactant deformations. The latter is due to steric interactions. (C) 2000 Elsevier Science Ltd. All rights reserved.
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页码:2547 / 2559
页数:13
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