Synergistic Transition Metal and Hydrogen Bonding Phase-Transfer Catalysis Enables Enantioconvergent Allylic Fluorination with KF

Synergistic catalysis whereby both the nucleophile and the electrophile can be simultaneously activated by two distinct catalysts can rescue otherwise unattainable chemical transformations, as well as create or improve catalytic enantioselectivity. Herein, we report the merging of transition metal and hydrogen bonding phase-transfer catalysis to allow for allyl bromides to undergo enantioselective fluorination with KF. Individually, these two catalytic strategies are ineffective. Beyond solving the issue of reactivity, this approach represents a new manifold for enantiocontrol with a chiral ion pair composed of a metal-activated electrophilic substrate and a chiral hydrogen-bonded nucleophile. This study offers fresh opportunities for designing catalytic fluorination with high reactivity and enantioselectivity across diverse metal complexes and KF.