Pyrazino O Quinodimethanes from PyrazineFused 3Sulfolenes

We have developed a simple one-pot reaction to synthesize pyrazino-3-sulfolenes 7a–c. The synthesis was accomplished by treating a mixture of an αdicarbonyl 14a-c and 3,4-diazido-2-sulfolene 13 in the presence of PPh3. The corresponding o-quinodimethanes were generated by thermolysis of 7a-c and trapped with dienophiles.