Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, China.
Org Lett. 2022 Jan 28;24(3):815-820. doi: 10.1021/acs.orglett.1c03992. Epub 2022 Jan 12.
A coupling of acrylic acids/benzoic acids with α-diazocarbonyl compounds has been realized by a combined catalytic system of rhodium catalyst and Zn(OAc) additive. The presence of Zn(OAc) obviously accelerates the C(sp)-H activation and destructed the formation of carboxylic ester that is formed via a nucleophilic O-H insertion to metal carbenoid. The procedure featured mild reaction conditions and broad substrate scope, providing a straightforward approach to the synthesis of α-pyrones and isocoumarins without the transformation of carboxylic acids to the corresponding amides.
通过铑催化剂和 Zn(OAc)添加剂的组合催化体系，实现了丙烯酸/苯甲酸与α-重氮羰基化合物的偶联。Zn(OAc)的存在明显加速了 C(sp)-H 的活化，并破坏了通过亲核 O-H 插入到金属碳烯形成的羧酸酯的形成。该方法具有温和的反应条件和广泛的底物范围，提供了一种无需将羧酸转化为相应酰胺即可合成α-吡喃酮和异香豆素的简便方法。
