Diastereo- and Enantioselective Propargylation of 5H-Thiazol-4-ones and 5H-Oxazol-4-ones as Enabled by Cu/Zn and Cu/Ti Catalysis.

Reported is the asymmetric propargylic substitution (APS) reaction of 5H-thiazol-4-ones using a Cu/Zn dual metal catalytic system and the APS reaction of 5H-oxazol-4-ones using a Cu/Ti catalytic system. These reactions furnish functional-group-rich, terminal-alkyne-containing products with two vicinal stereocenters in high yields and with good to excellent diastereo- and enantioselectivities. This study demonstrates the use of dual metal catalytic systems as a viable approach to improve the selectivity profiles of the copper-catalyzed APS reactions.