Controlling the α/γ‐Reactivity of Vinylogous Ketone Enolates in Organocatalytic Enantioselective Michael Reactions. (20th June 2017)

• Record Type: Journal Article
• Authors: Iriarte, Igor; Olaizola, Olatz; Vera, Silvia; Gamboa, Iñaki; Oiarbide, Mikel; Palomo, Claudio
• Is Part Of: Angewandte Chemie. Volume 129:Number 30(2017)
• Page Start: 8986
• Page End: 8990
• Publication Date: 2017-06-20
• Subjects: Brønsted-Basen -- Ketone -- Konjugierte Additionen -- Organokatalyse -- Regioselektivität; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201703764
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The first regio‐, diastereo‐, and enantioselective direct Michael reaction of β, γ‐unsaturated ketones with nitroolefins is enabled by Brønsted base/hydrogen‐bonding bifunctional catalysis. A squaramide‐substituted tertiary amine catalyzes the reaction of a broad range of β, γ‐unsaturated ketones to proceed at the α‐site exclusively, giving rise to adducts with two consecutive tertiary carbon stereocenters in diastereomeric ratios of up to >20:1 and enantioselectivities generally in the 90–98 % ee range.