Carboxy(vinyl)ketene intermediates in the thermolysis of methylthio- and methoxy-substituted Meldrum’s acid derivatives
作者:Hervé Bibas、C. Oliver Kappe、Ming Wah Wong、Curt Wentrup
DOI:10.1039/a708585k
日期:——
flash vacuum thermolysis (FVT) of Meldrum’s acid derivatives 7 and 13a. Methylthio(methyl)methyleneketene 9 and alkoxy(methyl)methyleneketene 15 are formed concurrently at high FVT temperatures. The alkoxy(methyl)methyleneketenes 15 do not isomerise to alkoxy(vinyl)ketenes 18, which have been generated and identified in other reactions. Ethoxy(methyl)methyleneketene 15b readily eliminates ethene in
在梅德鲁姆酸衍生物7和13a的快速真空热解(FVT)之后,通过Ar矩阵分离FTIR光谱鉴定了甲硫基和甲氧基取代的羧基(乙烯基)乙烯酮10和16a。在高FVT温度下同时形成甲硫基(甲基)亚甲基乙烯酮9和烷氧基(甲基)亚甲基乙烯酮15。烷氧基(甲基)亚甲基烯酮15不异构化为已在其他反应中生成和鉴定的烷氧基(乙烯基)烯酮18。乙氧基(甲基)亚甲基乙烯酮15b在逆烯型反应中容易地除去乙烯,从而生成乙酰基乙烯酮22。酮烯酮15与醇和胺反应,生成3-烷氧基丁烯酸衍生物21。