作者:Mark McLaughlin、Karen Marcantonio、Cheng-yi Chen、Ian W. Davies
DOI:10.1021/jo800321p
日期:2008.6.1
approach for the regiocontrolled preparation of pyrazoles bearing substituents on all three carbon atoms is described. Central to this method is the use of a switchable metal-directing group (MDG) to enable sequential direct lithiation of the 3- and 5-positions of the pyrazole ring. Pyrazole boronic esters obtained from these lithiated intermediates can undergo efficient Suzuki cross-coupling under
描述了用于在区域上可控制地制备在所有三个碳原子上均带有取代基的吡唑的模块化方法。该方法的核心是使用可转换的金属导向基团(MDG),以实现吡唑环的3位和5位的顺序直接锂化。从这些锂化中间体获得的吡唑硼酸酯可以在开发的非水条件下进行有效的Suzuki交叉偶联,从而将不良的蛋白水解性脱硼降至最低。4-位的卤代提供了在剩余的碳原子上进行取代的手段。