Intramolecular inverse electron demand Diels-Alder reactions of pyrazines
作者:Marek Biedrzycki、Dick A de Bie、Henk C van der Plas
DOI:10.1016/s0040-4020(01)85132-2
日期:1989.1
Thermally induced intramolecularDiels-Alder cyclisations of (alkynyloxyalkyl)pyrazines to dihydropyranopyridines have been studied in the solvent undecane. The introduction of a phenyl group in the α-position of the 3-butynyloxymethyl sidechain leads to a 3–4 fold increase of the reaction rate, while the influence of a γ-phenyl group on the rate is negligible. The (3-butynyloxymethyl)pyrazine reacts about