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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.

以乙烯基自由基与CO反应为基础，研究了α-烯酮自由基的合成化学，研究了以（TMS）3SiH（TTMSS）和正己烷为自由基介质，1，5-烯炔的自由基羰基化反应，α，β-不饱和酰基在C-C双键上5-外环化生成环戊酮。炔胺与氢化三丁基锡自由基羰基化反应生成α-亚甲基内酰胺和α-锡基亚甲基内酰胺的混合物。环化反应的关键步骤是在α-烯酮的羰基上亲核加成一个内氨基。随后从所得的1-羟基烯丙基自由基发生不寻常的1，4-H位移，然后消除β-三丁基锡自由基，从而形成α-亚甲基内酰胺。这种自由基/离子结合的概念可以扩展到包括α-烯酮基与胺的分子间跳闸反应。在过量胺存在下，用加压一氧化碳、氢化三丁基锡（30mol%）和AIBN处理末端炔，得到了较好的α-亚甲基酰胺产率。生成的α-烯酮基自由基然后通过胺亲核捕获羰基，导致产生1-羟基烯丙基自由基，1，4-H迁移得到α-酮基自由基，β-消除得到三丁基锡自由基和α-烷基丙烯酰胺。这些研究成果为α-烯酮自由基催化炔羰基化反应提供了新的途径。