Abstract
Herein we report the first use of vinyl and heteroaryl trifluoroborate salts as viable substrates for amine-catalyzed conjugate additions. The application of LUMO-lowering iminium catalysis has enabled the highly regio- and enantioselective 1,4-addition of rationally designed trifluoroborate salt nucleophiles to α,β-unsaturated aldehydes. Imidazolidinone 2•HCl was found to catalyze the addition of various BF3K-derived heteroaryl and vinyl species to a range of enals with excellent levels of enantioselectivity. Importantly, the use of these salts can enable nontraditional regiocontrol as part of a Friedel−Crafts pathway. Boronic acids can also be employed as viable π-nucleophiles for these asymmetric conjugate additions provided that in situ activation to the corresponding boronate species is accomplished. While BF3K salts are routinely employed in transition metal catalysis, to our knowledge, this is the first use of this activation group for organic catalysis or Friedel−Crafts alkylations.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
