Enantioselective Formal [3+2] Cycloaddition of Epoxides with Imines under Brønsted Base Catalysis: Synthesis of 1, 3‐Oxazolidines with Quaternary Stereogenic Center. Issue 21 (26th April 2018)

• Record Type: Journal Article
• Authors: Kondoh, Azusa; Akahira, Shiori; Oishi, Masafumi; Terada, Masahiro
• Is Part Of: Angewandte Chemie international edition. Volume 57:Issue 21(2018)
• Page Start: 6299
• Page End: 6303
• Publication Date: 2018-04-26
• Subjects: asymmetric catalysis -- Brønsted base -- cycloaddition -- heterocycles -- organocatalysis; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201802468
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: The formal [3+2] cycloaddition of epoxides and unsaturated compounds is a powerful methodology for the synthesis of densely functionalized five‐membered heterocyclic compounds containing oxygen. Described is a novel enantioselective formal [3+2] cycloaddition of epoxides under Brønsted base catalysis. The bis(guanidino)iminophosphorane as a chiral organosuperbase catalyst enabled the enantioselective reaction of β, γ ‐epoxysulfones with imines, owing to its strong basicity and high stereocontrolling ability, to provide enantioenriched 1, 3‐oxazolidines having two stereogenic centers, including a quaternary one, in a highly diastereo‐ and enantioselective manner. Abstract : It's superbase ! A novel enantioselective formal [3+2] cycloaddition of epoxides was developed under Brønsted base catalysis. The bis(guanidino)iminophosphorane, as a chiral organosuperbase catalyst, enabled the enantioselective reaction of β, γ ‐epoxysulfones with imines, owing to its high basicity and ability for good stereocontrol, to provide enantioenriched 1, 3‐oxazolidines having two stereogenic centers, including a quaternary one, in a highly diastereo‐ and enantioselective manner. Boc= ter t‐butoxycarbonyl.