Brønsted Base‐Catalyzed Umpolung Intramolecular Cyclization of Alkynyl Imines. Issue 16 (16th February 2018)

• Record Type: Journal Article
• Authors: Kondoh, Azusa; Terada, Masahiro
• Is Part Of: Chemistry. Volume 24:Issue 16(2018)
• Page Start: 3998
• Page End: 4001
• Publication Date: 2018-02-16
• Subjects: Brønsted base catalysis -- intramolecular cyclization -- organocatalysts -- rearrangement -- umpolung; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.201800219
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A novel "umpolung" intramolecular cyclization of alkynyl imines, in which the electrophilic imine sp 2 ‐carbon formally serves as a nucleophilic site, was developed under Brønsted base catalysis. The reaction involves the unprecedented catalytic generation of α‐aminoester enolates from α‐iminoesters via the 1, 2‐addition of the anion of a secondary phosphite to an imine moiety followed by the [1, 2]‐rearrangement of a dialkoxyphosphoryl moiety from carbon to nitrogen, which is a formal umpolung process, and the intramolecular addition to an alkyne. This is a rare example of a [1, 2]‐rearrangement of a dialkoxyphosphoryl moiety from carbon to nitrogen to generate an α‐amino carbanion and the first catalytic carbon–carbon bond forming reaction utilizing the resulting carbanion as a nucleophile. Abstract : A novel "umpolung" intramolecular cyclization of alkynyl imines, in which the electrophilic imine sp 2 ‐carbon formally serves as a nucleophilic site, was developed under Brønsted base catalysis. This is a rare example of a [1, 2]‐rearrangement of a dialkoxyphosphoryl moiety from carbon to nitrogen to generate an α‐amino carbanion and the first catalytic carbon–carbon bond‐forming reaction utilizing the resulting carbanion as a nucleophile.