Neat carbomethoxypivaloylketene, the first fairly persistent α-oxoketene stabilized both electronically as well as sterically, is generated by flash vacuum pyrolysis of the corresponding furan-2,3-dione. It adds primary amines to afford pivaloyl-malonic acid amides and undergoes hetero-Diels–Alder reactions to furnish usual and unusual [4+2] adducts. Some stereo- and regiochemical features are verified
Synthesis and chemical reactivity of methoxycarbonyl-1,3-dioxinyl(pivaloyl)ketene—a persistent α-oxoketene
作者:Bianca C. Wallfisch、Ferdinand Belaj、Curt Wentrup、C. Oliver Kappe、Gert Kollenz
DOI:10.1039/b111143d
日期:2002.2.22
Flash vacuum pyrolysis of an equimolar mixture of 4-pivaloyl- and 4-methoxycarbonyl-5-tert-butylfuran-2,3-dione affords the new and remarkably stable α-oxoketene 6 as the result of an unusual dimerization of the primarily formed monomeric α-oxoketenes 1 and 3, respectively. [2 + 2] Cycloaddition reactions of 6 and dialkylcarbodiimides furnish functionalized imino-β-lactams 7, while reaction with nucleophiles