一种新型的铜( II )催化级联Csp 2 –P/C–C键形成在邻卤代芳基异硫氰酸酯与有机磷酯中在温和条件下被开发出来。以中等至良好的产率合成了一系列苯并[ d ]噻唑-2-基膦酸酯。与传统通过自由基反应获得这些支架的方法不同,该方法可以通过离子反应获得它们,具有原料易得、操作简单的优点。最后,我们进行了克级实验,以进一步证明该策略在苯并[ d ]噻唑-2-基膦酸酯的高效合成中的可扩展性。
Palladium-catalyzed direct phosphonation of azoles with dialkyl phosphites
作者:Chaodong Hou、Yunlai Ren、Rui Lang、Xiaoxue Hu、Chungu Xia、Fuwei Li
DOI:10.1039/c2cc30429e
日期:——
The first Pd-catalyzed direct phosphonation of azoles with dialkyl phosphites has been achieved without addition of base or acid. This method involves the oxidative cleavage of C-H and P(O)-H bonds and represents an atom-efficiency alternative to the classical phosphonation of Ar-X. A Pd(II)/Pd(IV) mechanism has been studied and proposed.
Peroxides as “Switches” of Dialkyl <i>H</i>-Phosphonate: Two Mild and Metal-Free Methods for Preparation of 2-Acylbenzothiazoles and Dialkyl Benzothiazol-2-ylphosphonates
Two mild and metal-free methods for the preparation of two kinds of important benzothiazole derivatives, 2-acylbenzothiazoles and dialkyl benzothiazol-2-ylphosphonates, respectively, were developed. The diallcyl H-phosphonate (RO)(2)P(O)H exists in equilibrium with its tautomer dialkyl phosphite (RO)(2)POH. TBHP triggered alpha-carbon-centered phosphite radical formation, whereas DTBP triggered phosphorus-centered phosphonate radical formation. The two types of radicals led respectively to two different reaction processes, the direct C-2-acylation of benzothiazoles and C-2-phosphonation of benzothiazoles.