AbstractExclusive formation of 5‐aryl‐2‐trimethylsilyl‐4H‐pyran‐4‐ones is accomplished by a regioselective cyclization of 2‐aryl‐1‐ethoxy(hydroxy)‐5‐(trimethylsilyl)pent‐1‐en‐4‐yn‐3‐ones. This cyclization occurs in a 6‐endo‐dig mode through addition to the β‐atom of the TMS substituted triple bond. The reaction was found to be general for a range of ethoxyenynones upon heating in glacial acetic acid and for analogous hydroxyenynones in diphenyl ether. Plausible mechanistic explanation and possible post‐modifications of resulting pyranones are offered.
摘要通过 2-芳基-1-乙氧基(羟基)-5-(三甲基硅基)戊-1-烯-4-炔-3-酮的区域选择性环化,独家形成了 5-芳基-2-三甲基硅基-4H-吡喃-4-酮。这种环化以 6-endo-dig 模式通过与 TMS 取代的三键的β原子加成而发生。研究发现,在冰醋酸中加热时,一系列乙氧基炔酮和二苯醚中的类似羟基炔酮都会发生这种反应。该研究提供了合理的机理解释,并对由此产生的吡喃酮进行了可能的后修饰。