Diels–Alder Cycloaddition of Chiral Nonracemic 2,5-Diketopiperazine Dienes

Preparation of a chiral, nonracemic 2,5-diketopiperazine diene has enabled the investigation of intermolecular hetero-Diels–Alder cycloadditions. The diketopiperazine diene is reactive with both electron-rich and -deficient alkene substrates. Diastereofacial control in the cycloaddition is enforced with a removable aminal substituent. This study partly illuminates the regiochemical, stereoelectronic, and reactivity preferences of the diketopiperazine cycloaddition as well as provides a direct diastereoselective synthetic route to bicyclo[2.2.2]diazaoctane structures.