Rh(II)-Catalyzed Ring Expansion of Pyrazoles with Diazocarbonyl Compounds as a Method for the Preparation of 1,2-Dihydropyrimidines
作者:Alexander N. Koronatov、Nikolai V. Rostovskii、Alexander F. Khlebnikov、Mikhail S. Novikov
DOI:10.1021/acs.joc.8b01228
日期:2018.8.17
A high yield synthesis of 1,2-dihydropyrimidines by the Rh(II)-catalyzed reaction of diazocarbonyl compounds with 1,4-di- and 1,4,5-trisubstituted pyrazoles is reported. This reaction represents the first example of a carbenoid insertion into a N–N bond and provides a novel approach to 4-unsubstituted 1,2-dihydropyrimidines with a broad range of functional group tolerance. According to DFT calculations
报道了通过Rh(II)催化的重氮羰基化合物与1,4-二-和1,4,5-三取代的吡唑的高产率合成1,2-二氢嘧啶。该反应代表类胡萝卜素插入N–N键的第一个例子,它为具有范围广泛的官能团耐受性的4-未取代的1,2-二氢嘧啶提供了一种新颖的方法。根据DFT计算,吡唑环的扩环是通过依次形成与金属结合的吡唑鎓叶立德,无金属吡唑鎓叶立德和1,5-二氮杂己三烯并随后进行1,6-环化而进行的。