A new process for the utilization of carbon dioxide to give high value added 1,3-oxazine-2,4-diones is presented. It is based on the catalytic carboxylative heterocyclization of readily available 3-ynamides, using 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) as organocatalyst. The reaction, which takes place under relatively mild conditions [80 °C for 15 h in a 3:1 mixture (v/v) of MeCN-HC(OMe)₃, under 30 atm of CO₂] proceeds through an ordered sequence of steps, involving substrate deprotonation by DBU, nucleophilic attack to CO₂, 6-exo-dig cyclization, and isomerization, to give the final products in 44–85 % yields over 16 examples.

提出了一种利用二氧化碳生产高附加值 1,3-恶嗪-2,4-二酮的新工艺。它基于容易获得的 3-炔酰胺的催化羧化杂环化，使用 1,8-二氮杂双环 [5.4.0] 十一碳-7-烯 (DBU) 作为有机催化剂。该反应在相对温和的条件下进行 [80 °C，在 3:1 的 MeCN-HC(OMe) ₃混合物 (v/v) 中，在 30 个大气压的 CO ₂下进行 15 小时]包括通过 DBU 进行底物去质子化、对 CO _{2 的}亲核攻击、6- exo - dig环化和异构化的步骤，在 16 个实例中以 44-85% 的产率得到最终产物。