Enantioselective Synthesis of Dihydropyrazoles by Palladium/Xu‐Phos‐Catalyzed Alleneamination of β,γ‐Unsaturated Hydrazones with Propargylic Acetates
Shuting Zhang, Shuaijie Wu, Qiang Wang, Shiji Xu, Ying Han, Chao‐Guo Yan, Junliang Zhang, Lei Wang
Abstract
The palladium-catalyzed asymmetric carboamination reaction is one of the most significant transformations in organic chemistry. Herein, we report the first palladium-catalyzed asymmetric alleneamination of β,γ-unsaturated hydrazones with propargylic acetates. This protocol enables the efficient installation of various multisubstituted allene groups onto dihydropyrazoles in good yields with excellent enantioselectivities. The chiral sulfinamide phosphine ligand Xu-5 exhibits highly efficient stereoselective control in this protocol. The salient features of this reaction include the readily available starting materials, a broad substrate scope, an easy scale-up, mild reaction conditions and versatile transformations.