Synthesis of heterocyclic propellanes using Mn(III)-based oxidative cyclization

The manganese(III)-based oxidative cyclization of 1,1-diarylethenes 1 with 3-(2-oxoethyl)piperidine-2,4-diones 2 was carried out in acetic acid at reflux temperature to selectively produce azadioxa[4.3.3]propellanes 3 in high yields. A similar cyclization with the 2-(2-oxoethyl)cycloalkane-1,3-diones 7 and 2-(3-oxopropyl)cycloalkane-1,3-diones 10 also gave the corresponding dioxapropellanes 8 and 11 in moderate to good yields.