A Study of Vinyl Radical Cyclization onto the Azido Group by Addition of Sulfanyl, Stannyl, and Silyl Radicals to Alkynyl Azides⋆
作者:Pier Carlo Montevecchi、Maria Luisa Navacchia、Piero Spagnolo
DOI:10.1002/(sici)1099-0690(199806)1998:6<1219::aid-ejoc1219>3.0.co;2-v
日期:1998.6
1-Phenylvinyl radicals 23 and 30a, as well as vinyl radical 30b, undergo fast 5-cyclization onto the aromatic azide function to give cyclized indoles. In contrast, both 1-phenyl (15, 17) and 1-alkyl (3a,b, 9) vinyl radicals fail to add to their aliphatic azido substituents and exclusively undergo cyclization onto the aromatic sulfanyl ring and H transfer from the thiol precursor. Azidoalkynes 14 and
叠氮炔 2、8、14 和 21a-c 与硫醇 1a-c 的热自由基反应通过硫烷基自由基选择性加成到三键上,得到 2-硫烷基乙烯基自由基。1-苯基乙烯基基团 23 和 30a 以及乙烯基基团 30b 快速 5 环化到芳族叠氮化物官能团上,得到环化吲哚。相比之下,1-苯基 (15, 17) 和 1-烷基 (3a,b, 9) 乙烯基都无法添加到它们的脂肪族叠氮基取代基上,并且只会环化到芳族硫基环上,并且从硫醇前体转移 H。叠氮炔 14 和 21a 在自由基条件下与 Bu3SnH 和 TMSS 反应生成相应的胺,因为 Bu3Sn· 和 (TMS)3Si· 自由基优先攻击叠氮基而不是三键。