Generation and Cyclization of Unsaturated Carbamoyl Radicals Derived from <i>S</i>-4-Pentynyl Carbamothioates under Tin-Free Conditions
作者:Luisa Benati、Giorgio Bencivenni、Rino Leardini、Matteo Minozzi、Daniele Nanni、Rosanna Scialpi、Piero Spagnolo、Giuseppe Zanardi
DOI:10.1021/jo0602064
日期:2006.4.1
The radical reaction of benzenethiol with S-4-pentynyl carbamothioates provides a valuable protocol for the tin-free generation of carbamoyl radicals, which arise from intramolecular substitution at sulfur by the initial sulfanylvinyl radicals. This procedure can be usefully employed to achieve N-benzylcarbamoyl radical 5-exo and 4-exo cyclizations leading, respectively, to pyrrolidinones and azetidinones
苯硫酚与S -4-戊炔基氨基甲酸酯的自由基反应为无锡生成氨基甲酰基自由基提供了有价值的方案,该氨基甲酰基自由基是由硫在分子内被初始的硫烷基乙烯基自由基取代而产生的。该方法可以有效地用于实现分别导致吡咯烷酮和氮杂环丁烷酮的N-苄基氨基甲酰基自由基5-exo和4-exo环化,尽管对于后者而言,其效用较小。提出了新的证据,N-甲苯磺酰基取代的氨基甲酰基自由基表现出通过β-消除甲苯磺酰基自由基产生相应的异氰酸酯的独特趋势。