Interaction of beta-lactam carbenes with aryl isonitriles: an unprecedented rearrangement of 2-azetidinonylidene indoles to delta-carbolinones.
The reaction of beta-lactam carbenes with aryl isonitriles proceeded in a novel [2 + 2] fashion to give high yields of 2-azetidinonylidene indoles 4, which underwent an unprecedented rearrangement to furnish 4-arylimino-delta-carbolin-2-ones 5 in almost quantitative yields. Acid catalyzed rearrangement and the subsequent hydrolysis of 2-azetidinonylidene indoles 4 produced two types of delta-carbolin-2,4-diones 10 and 11, respectively, in good to excellent yields. The photophysical study showed that both delta-carbolin-2,4-diones 10 and 11 are highly fluorescent with the fluorescent quantum yields being up to 0.43.
Cheng
Ying
Y
Chemistry Department, Beijing Normal University, Beijing 100875, China. ycheng2@bnu.edu.cn
Cheng
Lan-Qing
LQ