Convenient construction of dibenzo[b,d]furanes and 2,6-diaryl-4-(2-hydroxyphenyl)pyridines via domino reaction of pyridinium ylides with 2-aryl-3-nitrochromenes

Abstract

The DBU promoted domino annulation reaction of 2-aryl-3-nitrochromenes with two molecular 4-(N,N-dimethylamino)-1-phenacylpyridinium bromides in DMF resulted in unprecedented 1-benzoyl-2,4-diaryldibenzo[b,d]furane derivatives in good yields, in which the six-membered pyran ring was readily converted to the five-membered furan ring. On the other hand, the three-component reaction of ammonium acetate, 2-aryl-3-nitrochromenes and 4-(N,N-dimethylamino)-1-phenacylpyridinium bromides in refluxing ethanol afforded 2,6-diaryl-4-(2-hydroxyphenyl)pyridines in high yields.