In this work, a novel C(sp3)–C(sp2) cross-dehydrogenative-coupling method is developed to react benzoxazin-2-one derivatives with various indoles. As a result, combined use of ball milling and Fe(ii) catalysis leads to rapid coupling of 1,4-benzoxazinones with derivatives of indole. Under the conditions, derivatives of 1 couple with various indoles at room temperature to produce good yields of the desired compounds within 0.5–2 h time period. Thus, derivatives of both starting materials couple smoothly under relatively mild conditions to give good yields of 3.

A new method was developed for C(sp 3 )-C(sp 3 ) oxidative dehydrogenative coupling of 1,4-benzoxazin-2-ones with malonate derivatives under ball milling to obtain the respective malonate esters. Reactions take place under solvent-free conditions using FeCl2.2H2O and DDQ as the catalyst and the oxidant. Conditions are relatively mild and the target products are obtained in high yields within 3-5 h time period.