Microwave Enhanced Tandem 5-<i>exo</i>Cyclization/Claisen Rearrangement Reactions: A Convenient Route to Cycloheptanoid Ring Systems
作者:Timo Ovaska、Caitlin McIntosh、Isamir Martínez
DOI:10.1055/s-2004-834790
日期:——
The use of microwave irradiation was found to significantly accelerate a one-pot reaction sequence involving a base-catalyzed 5-exo cyclization of appropriately substituted 4-alkyn-1-ols and subsequent Claisen rearrangement of the intermediate 2-methylene tetrahydrofuran derivatives. In most cases, the resulting cycloheptanoid ring systems were produced in a matter of minutes when subjected to microwave irradiation. The use of solvent-free conditions was also found to be compatible with the reaction sequence.
研究发现,使用微波辐照可以显著加快一锅反应序列,该序列涉及碱催化适当取代的 4- 烷醇的 5-外向环化,以及随后中间 2-亚甲基四氢呋喃衍生物的克莱森重排。在大多数情况下,微波辐照下几分钟就能生成环庚烷环系统。研究还发现,使用无溶剂条件与反应顺序也是相容的。