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Synthetic Reactions of α-Ketenyl Radicals Based on Radical Carbonylations

基于自由基羰基化的α-烯烯基自由基的合成反应

基本信息

批准号：
15350061
负责人：
RYU Ilhyong
金额：
$ 8.83万
依托单位：
Osaka Prefecture University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

项目摘要

Synthetic chemistry of a-ketenyl radicals was investigated based on the reaction of vinyl radicals and CO. The radical carbonylation of 1,5-enynes was investigated using (TMS)_3SiH (TTMSS) and hexanethiol as radical mediator, which gave cylopentanones via 5-exo cyclization of α,β-unsaturated acyl radicals onto C-C double bond. Radical carbonylation of alkynylamines with tributyltin hydride gives a mixture of α-methylene lactams and α-stannylmethylene lactams. Nucleophilic addition of an internal amino group to the carbonyl group of α-ketenyl radicals is suggested as the key cyclization step. The subsequent unusual 1,4-H shift from the resulting 1-hydroxyallyl radical, followed by elimination of the β-tributyltin radical leads to the formation of α-methylene lactams. This radical/ionic combined concept can be extended to include intermolecular tripping reactions of α-ketenyl radicals by amines. The treatment of terminal alkynes with pressurized carbon monoxide, tributyltin hydride (30 mol%) and AIBN in the presence of excessive amines, led to give good yields of α-methylene amides. The generated α-ketenyl radicals then undergo nucleophilic trapping of a carbonyl group by amines leading to the production of 1-hydroxyallyl radicals, 1,4-H migration to give α-keto radicals, and β-elimination to give the tributyltin radical and α-alkyl acrylic amides. All these achievements represent new methods for alkyne carbonylations via α-ketenyl radicals.

基于乙烯基自由基和CO的反应研究了α-烯酮自由基的合成化学。以(TMS)_3SiH (TTMSS)和己硫醇为自由基介体，研究了1,5-烯炔的自由基羰基化反应，通过α,β-不饱和酰基自由基在C-C双键上的5-外环化得到环戊酮。炔基胺与氢化三丁基锡的自由基羰基化得到α-亚甲基内酰胺和α-甲锡烷基亚甲基内酰胺的混合物。建议将内部氨基亲核加成到 α-烯酮基的羰基上作为关键的环化步骤。随后产生的 1-羟基烯丙基发生异常的 1,4-H 转变，随后消除 β-三丁基锡自由基，导致形成 α-亚甲基内酰胺。这种自由基/离子组合概念可以扩展到包括胺对 α-烯酮自由基的分子间脱扣反应。在过量胺存在下，用加压一氧化碳、氢化三丁基锡（30 mol%）和 AIBN 处理末端炔烃，可得到良好收率的 α-亚甲基酰胺。生成的 α-烯酮基自由基随后经历胺对羰基的亲核捕获，从而产生 1-羟基烯丙基自由基，1,4-H 迁移得到 α-酮基自由基，以及 β-消除得到三丁基锡自由基和 α-烷基丙烯酰胺。所有这些成就代表了通过 α-烯酮基自由基进行炔烃羰基化的新方法。