Fig. 1: The synthetic methods of hindered ether.

a The traditional Williamson method for the synthesis of ethers. b Baran’s decarboxylative etherification method for the synthesis of hindered ethers. c Cu-catalyzed enantioconvergent substitution reaction of a-haloamides with oxygen nucleophiles to a-oxygenated amides. d This work: Enantio- and diastereo-divergent Ca(II)/Au(I) synergistic catalysis for synthesis of chiral hindered ether.