Photoinduced Cyclization of 3-Acyl-2-halo-1-[(蠅-phenylethynyl)alkyl]indoles to Azaheterocyclo[1,2,3-lm]-Fused Benzo[c]carbazoles

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• 作者：Shenci Lu ; Ren Wang ; Yi Yang ; Yang Li ; Zongjun Shi ; Wei Zhang ; Zhifeng Tu
• 刊名：Journal of Organic Chemistry
• 出版年：2011
• 出版时间：July 15, 2011
• 年：2011
• 卷：76
• 期：14
• 页码：5661-5669
• 全文大小：997K
• 年卷期：v.76,no.14(July 15, 2011)
• ISSN：1520-6904

文摘

A one-pot synthesis of azaheterocyclo[1,2,3-lm]-fused benzo[c]carbazoles (2 and 3) has been developed by photocyclization of 3-acyl-2-halo-1-[(蠅-phenylethynyl)alkyl] indoles (1) in good to excellent yields. All products are formed from 1 via two sequential photocyclization reactions. Two products, 9-chloro-7,8-dihydro-6H-benzo[c]pyrido[1,2,3-lm]carbazole (2a鈥?b>h) and 7,8-dihydro-6H-benzo[c]pyrido[1,2,3-lm]carbazole (3a鈥?b>h), are produced in the photocyclization of 2-halo-1-[(蠅-phenylethynyl)alkyl]indole-3-carbaldehydes (1a鈥?b>h). In contrast, only products 2a鈥?b>h are produced in the photocyclization of 3-acetyl-2-chloro-1-[(蠅-phenylethynyl)alkyl]indole-3-carbaldehydes (1o鈥?b>t). The 9-H in 3a鈥?b>h (n = 2) does originate from the formyl group in 1a鈥?b>h via 1,5-hydrogen shift. The structures of three new products, 9-bromo-7,8-dihydro-6H-benzo[c]pyrido[1,2,3-lm]carbazole (2b), 9-chloro-10-methyl-7,8-dihydro-6H-benzo[c]pyrido[1,2,3-lm]carbazole (3h) and 12-chloro-7,8-dihydro-6H-benzo[c]pyrido[1,2,3-lm]carbazole (2w), have been corroborated by single-crystal X-ray structural analyses.