Transformation of Carbonyl Compounds into Homologous Alkynes under Neutral Conditions: Fragmentation of Tetrazoles Derived from Cyanophosphates
作者:Hiroki Yoneyama、Masahiro Numata、Kenji Uemura、Yoshihide Usami、Shinya Harusawa
DOI:10.1021/acs.joc.7b00346
日期:2017.6.2
Cyanophosphates (CPs) can be easily prepared from either ketones or aldehydes, and their reaction with NaN3–Et3N·HCl results in the formation of azidotetrazoles. Under microwave irradiation, successive fragmentation of the azidotetrazoles generates alkylidene carbenes that undergo [1,2]-rearrangement and are transformed into homologous alkynes. Treatment of ketone-derived CPs with TMSN3 and Bu2SnO
氰基磷酸盐(CPs)可以很容易地从酮或醛中制备,它们与NaN 3 -Et 3 N·HCl的反应导致叠氮四唑的形成。在微波辐射下,叠氮四唑的连续断裂产生亚烷基卡宾,经过[1,2]重排并转化为同源炔烃。用TMSN 3和Bu 2 SnO作为催化剂在甲苯中回流处理酮衍生的CP,可直接产生相应的内部炔烃,而醛衍生的CP与NaN 3 -Et 3 N·HCl在THF中的回流或TMSN 3反应–Bu 2回流中的甲苯中的SnO(催化)可提供高收率的同源末端炔烃。这些反应在中性条件下进行,可以成功地扩展以得到通常需要通过碱性条件的Ohira–Bestmann或Shioiri方法从相应的羰基化合物无法获得的炔烃。