Pd-Catalyzed Stereoselective Synthesis of Nitroalkyl -C-Glycosides

C-Glycosides have attracted more and more attention in the field of medicine and biology due to their excellent physiological activities and stability to hydrolysis/enzymolysis. However, the challenges of stereoselective control are still high during the synthesis process. In this paper, a method for preparing beta-C-glycosides with high stereoselectivity through the reaction of 3,4-O-carbonate-D-galactal and nitroalkane with Pd(acac)(2) and 1,4-bis(diphenylphosphino)butane (DPPB) ligand at room temperature has been reported. The structures of the target compounds have been determined by nuclear magnetic resonance spectroscopy (NMR), high-resolution mass spectra (HRMS) and X-ray single crystal diffraction. The method has a wide range of substrates, and has good compatibility for both electron-withdrawing and electron-donating nitroalkanes. Single beta-C-glycosides were obtained with high yields, which provide a reliable method for the rapid construction of C-glycoside libraries.