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A General and Highly Selective Palladium-Catalyzed Hydroamidation of 1,3-Diynes
2021, Liu, Jiawang, Schneider, Carolin, Yang, Ji, Wei, Zhihong, Jiao, Haijun, Franke, Robert, Jackstell, Ralf, Beller, Matthias
A chemo-, regio-, and stereoselective mono-hydroamidation of (un)symmetrical 1,3-diynes is described. Key for the success of this novel transformation is the utilization of an advanced palladium catalyst system with the specific ligand Neolephos. The synthetic value of this general approach to synthetically useful α-alkynyl-α, β-unsaturated amides is showcased by diversification of several structurally complex molecules and marketed drugs. Control experiments and density-functional theory (M06L-SMD) computations also suggest the crucial role of the substrate in controlling the regioselectivity of unsymmetrical 1,3-diynes. © 2020 The Authors. Published by Wiley-VCH GmbH
Ligand-Controlled Palladium-Catalyzed Carbonylation of Alkynols : Highly Selective Synthesis of α-Methylene-β-Lactones
2020, Ge, Yao, Ye, Fei, Liu, Jiawang, Yang, Ji, Spannenberg, Anke, Jiao, Haijun, Jackstell, Ralf, Beller, Matthias
The first general and regioselective Pd-catalyzed cyclocarbonylation to give α-methylene-β-lactones is reported. Key to the success for this process is the use of a specific sterically demanding phosphine ligand based on N-arylated imidazole (L11) in the presence of Pd(MeCN)2Cl2 as pre-catalyst. A variety of easily available alkynols provide under additive-free conditions the corresponding α-methylene-β-lactones in moderate to good yields with excellent regio- and diastereoselectivity. The applicability of this novel methodology is showcased by the direct carbonylation of biologically active molecules including natural products. © 2020 The Authors. Published by Wiley-VCH GmbH