Ab initio study of the effect of CH ··· O hydrogen bonding on the exo/endo stereoselectivity of Diels-Alder reactions of 2-substituted-1,3-dienes with sulfur dioxide

Ab initio calculations at the MP 2/6-31G *//HF /3-21G * level have been carried out to study Diels-Alder reactions of 2-substituted-1,3-dienes with sulfur dioxide. The CH ··· O electrostatic interaction detected in some of the transition structures located could be decisive in the control of the exo/endo stereoselectivity of this type of reaction. © 1996 John Wiley & Sons, Inc.