作者:Volker Belting、Norbert Krause
DOI:10.1039/b819704k
日期:——
Depending on the substitution pattern and the solvent, the gold-catalyzed cyclization of alk-4-yn-1-ones 1 affords different oxygen heterocycles under mild reaction conditions. Alkynones with one substituent at C-3 undergo a 5-exo-dig cycloisomerization to substituted furans 2, whereas a 6-endo-digcyclization to 4H-pyrans 3 is observed with substrates bearing two substituents at C-3. In alcoholic solvents
根据取代方式和溶剂的不同,在轻度的反应条件下,alk-4-yn-1-ones 1的金催化环化反应会产生不同的氧杂环。与C-3一个取代基Alkynones经过5 -外型-挖环异构取代的呋喃2,而6 -内-挖环化成4 ħ -pyrans 3与基板承载两个取代基在C-3观察到。在醇溶剂中,以串联亲核加成/环异构化反应形成亚烷基/亚苄基取代的四氢呋喃基醚4。