A chiral probe for the asynchronous transition state of Diels-Alder reactions with acetylenedicarboxylate

Article abstract of DOI:10.1016/S0040-4020(99)00982-5

Diels-Alder reactions took place with modest diastereoselectivity between dimethylcyclohexadiene derivative 3a and di-(-)-menthyl acetylenedicarboxylate, whereas the dimethylcyclohexadiene 2 showed no selectivity whatsoever. These results can be rationalized in terms of a complete lack of any endo-exo preference for the carboxylate groups and a more synchronous addition with 3a than with 2.