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Ab Initio Study of Endo / Exo and Diastereofacial Selectivities in Diels−Alder Reactions between Chiral Butenolides and Cyclopentadiene

1996; American Chemical Society; Volume: 61; Issue: 2 Linguagem: Inglês

10.1021/jo950541k

1520-6904

Abdelouahid Sbai, Vicenç, António Oliva,

Chemical Reaction Mechanisms

Diels−Alder reactions of cyclopentadiene with crotonolactone and β-angelica lactone have been studied using ab initio methods at the MP3/6-31G*//RHF/3-21G and MP2/6-31G*//RHF/6-31G* levels. The transition states corresponding to the formation of different stereoisomers and diastereoisomers have been located. The results obtained show that the correct endo/exo selectivity is only obtained when polarization functions are included in the basis set. However, syn/anti selectivity is correctly described at all levels of calculation.