2,5-diketopiperazines, new chiral auxiliaries for asymmetric Diels-Alder reactions

Article abstract of DOI:10.1016/S0040-4039(97)00769-7

Diketopiperazines have been utilized as chiral auxiliaries for asymmetric Diels-Alder reactions. Cyclo-S-phenylalanyl-R-proline (2) was found to be the most promising of these auxiliaries and afforded Diels-Alder adducts in high chemical yield (78-95%), with endo selectivities generally greater than 9:1. The diastereoselectivities observed were comparable to the best previously published values.