Iodine-Mediated Oxidative Annulation of β,γ-Unsaturated Hydrazones in Dimethyl Sulfoxide: A Strategy to Build 1,6-Dihydropyridazines and Pyrroles

• DOI: 10.1021/acs.joc.3c00669
• Publication Date: 2023-07-14T11:48:00Z
• Authors: Qianrui Liu; Jiaming Jiang; Xuanzeng Ye; Jiawen Sun; Yao Wu; Yinlin Shao; Chao Deng; Fangjun Zhang
• Keywords: Annulation; Chemoselectivity; Hydrazone

Simple, commercially available iodine was successfully employed as a highly efficient and chemoselective catalyst for the oxidative annulation of β,γ-unsaturated hydrazones to produce 1,6-dihydropyridazines under mild conditions first time. Interestingly, when active hydrazone compounds containing electron-donating groups, such furyl, thienyl, cycloalkyl, were used, pyrroles obtained. A gram-scale preparation experiment further derivatization pyridazines demonstrated potential applicability our synthesis method. Experimental studies density functional theory calculations unveiled origin chemoselectivity determining formation different products.