Ujaque Gregori, Lee Patrick S, Houk K N, Hentemann Martin F, Danishefsky Samuel J
Department of Chemistry and Biochemistry University of California, Los Angeles CA 90095-1569 USA.
Chemistry. 2002 Aug 2;8(15):3423-30. doi: 10.1002/1521-3765(20020802)8:15<3423::AID-CHEM3423>3.0.CO;2-X.
Theoretical studies of stereoselectivity have been carried out with B3LYP and MP2 calculations. The high endo selectivity of hetero-Diels-Alder reactions of ortho-xylylenes with acetaldehydes is shown to result from attractive CH-pi interactions between alkyl groups of the aldehyde and the aromatic ring in the transition states of the reaction. For the hetero-Diels-Alder reactions of ortho-xylylenes with benzaldehyde, the stereoselectivity is shown to be mainly governed by the attractive pi-pi interactions between the phenyl rings of the benzaldehyde and the ortho-xylylene. MP2 calculations are necessary to reproduce the stabilizing dispersion interactions.
已使用B3LYP和MP2计算对立体选择性进行了理论研究。邻亚二甲苯与乙醛的杂Diels-Alder反应的高内向选择性表明，这是由于醛的烷基与反应过渡态中的芳环之间存在吸引性的CH-π相互作用。对于邻亚二甲苯与苯甲醛的杂Diels-Alder反应，立体选择性主要由苯甲醛的苯环与邻亚二甲苯之间的吸引性π-π相互作用决定。必须进行MP2计算才能重现稳定的色散相互作用。
