Journal of the American Chemical Society, Vol.141, No.11, 4558-4563, 2019
Pd(II)-Catalyzed Enantioselective Alkynylation of Unbiased Methylene C(sp(3))-H Bonds Using 3,3 '-Fluorinated-BINOL as a Chiral Ligand
The first Pd(II)-catalyzed enantioselective alkynylation of unbiased methylene beta-C(sp(3))-H bonds is reported. The readily accessible and tunable BINOL derivatives are used as chiral ligands in C-H activation for the first time. 3,3'-Fluorinated-BINOL proved crucial in determining both the reactivity and enantioselectivity. A wide range of carboxylic acid derivatives are well tolerated with high enantioselectivities (up to 96% ee). Mechanistic studies suggest that multiple ligands may participate in the stereodetermining C-H palladation step, and a chiral amplification effect is observed.