Abstract
MacMillan and Lee describe an enantioselective conjugate addition of trifluoro(organo)borates to α,β-unsaturated aldehydes 1 catalyzed by amine 2. Potassium styryltrifluoroborate salts 3 and electron-deficient heteroaromatics as their potassium heteroaryl trifluoroborate salts 4 are employed as π-nucleophiles. Tryptophan-derived imidazolidinone catalyst 2 ·HCl converts a broad range of α,β-unsaturated aldehydes into vinyl (5) and heteroaryl (6) addition products, respectively. Good to excellent yields (69-97% yield) and good enantioselectivities (er = 93.5:6.5 up to 98.5:1.5) are obtained. Furthermore, non-traditional regiocontrol as part of a Friedel-Crafts alkylation is achieved (see example two).
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.
