Shi Shicheng, Szostak Michal
Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
Chem Commun (Camb). 2017 Sep 21;53(76):10584-10587. doi: 10.1039/c7cc06186b.
Amides are of fundamental interest in many fields of chemistry involving organic synthesis, chemical biology and biochemistry. Here, we report the first catalytic Buchwald-Hartwig coupling of both common esters and amides by highly selective C(acyl)-X (X = O, N) cleavage to rapidly access aryl amide functionality via a cross-coupling strategy. Reactions are promoted by versatile, easily prepared, well-defined Pd-PEPPSI type precatalysts, and proceed in good to excellent yields and with excellent chemoselectivity for the acyl bond cleavage. The method is user friendly because it employs commercially-available, moisture- and air-stable precatalysts. Notably, for the first time we demonstrate selective C(acyl)-N and C(acyl)-O cleavage/Buchwald-Hartwig amination under the same reaction conditions, which allows for streamlining amide synthesis by avoiding restriction to a particular acyl metal precursor. Of broad interest, this study opens the door to using a family of well-defined Pd(ii)-NHC precatalysts bearing pyridine "throw-away" ligands for the selective C(acyl)-amination of bench-stable carboxylic acid derivatives.
酰胺在涉及有机合成、化学生物学和生物化学的许多化学领域中都具有重要意义。在此，我们报道了首例通过高度选择性的C（酰基）-X（X = O，N）裂解实现常见酯和酰胺的催化布赫瓦尔德-哈特维希偶联反应，从而通过交叉偶联策略快速获得芳基酰胺官能团。反应由通用、易于制备且定义明确的Pd-PEPPSI型预催化剂促进，反应产率良好至优异，对酰基键裂解具有出色的化学选择性。该方法对用户友好，因为它使用市售的、对湿气和空气稳定的预催化剂。值得注意的是，我们首次证明了在相同反应条件下选择性的C（酰基）-N和C（酰基）-O裂解/布赫瓦尔德-哈特维希胺化反应，这通过避免对特定酰基金属前体的限制实现了酰胺合成的简化。这项研究具有广泛的意义，为使用一类带有吡啶“可抛弃”配体的定义明确的Pd（II）-NHC预催化剂对稳定的羧酸衍生物进行选择性C（酰基）-胺化反应打开了大门。
