Efficient Regioselective Opening of Epoxides by Nucleophiles in Water under Simultaneous Ultrasound/Microwave Irradiation
作者:Giancarlo Cravotto、Giovanni Palmisano、Silvia Tagliapietra、Alessandro Barge、Arianna Binello、Luisa Boffa
DOI:10.1055/s-2007-984891
日期:——
Epoxide cleavage by nucleophiles in aqueous media may suffer from competition by water itself, yielding the diol as byproduct. However, when the reaction was carried out under high-intensity ultrasound or microwaves, attack by the nucleophile was strongly promoted and water no longer reacted. Best results were achieved under simultaneous ultrasound/microwave irradiation: a series of mono-, di- and
在水性介质中亲核试剂对环氧化物的裂解可能会受到水本身的竞争,产生作为副产物的二醇。然而,当反应在高强度超声波或微波下进行时,亲核试剂的攻击被强烈促进,水不再反应。在同时超声/微波照射下取得了最好的结果:一系列单、二和三取代的环氧乙烷与叠氮化钠或 1-(3-氯苯基)哌嗪快速反应,通常会产生相应的更多取代的醇,收率可以接受到高收率. 这种无催化剂、更环保的方案以高区域选择性实现了环氧化物的更快裂解。