Pupo G,
Vicini AC,
Ascough DM. H,
Ibba F,
Christensen KE,
Thompson AL,
Brown JM,
Paton RS,
Gouverneur V.
* University of Oxford, UK and Colorado State University, Fort Collins, USA
Hydrogen Bonding Phase-Transfer Catalysis with Potassium Fluoride: Enantioselective
Synthesis of β-Fluoroamines.
J. Am. Chem. Soc. 2019;
141: 2878-2883
Key words
hydrogen-bonding phase-transfer catalysis - chiral bisurea catalysts - β-fluoroamines
- potassium fluoride
Significance
Gouverneur and co-workers report a nucleophilic fluorination of β-chloroamines by
using a chiral bisurea catalyst and KF or CsF as a solid source of fluoride in hydrogen-bonding
phase-transfer catalysis (HB-PTC). Both fluoride sources are easy to handle, nontoxic,
and cheap in comparison with other fluorination reagents. The β-fluoroamines were
obtained in high yields and high enantioselectivities, and, for some examples, on
a large scale.
Comment
The concept of HB-PTC was recently applied to nucleophilic fluorination reactions
by the authors (Science 2018, 360, 638). On the basis of this work, they were able to further decrease the cost of
the fluoride source, without loss of enantioselectivity, by using KF. Furthermore,
the authors approached a broader scope by using aziridinium ion precursors, which
led to the synthesis of several fluoro derivatives of approved drugs (e.g., diphenidine).
