Enantioselective [2 + 2] cycloaddition of N-allenamides with cyclic N-sulfonylketimines: access to polysubstituted azetidines bearing quaternary stereocenters

Enantioselective [2 + 2] cycloaddition of N-allenamides with cyclic N-sulfonylketimines: access to polysubstituted azetidines bearing quaternary stereocenters.

A Ni(ClO4)2-catalyzed enantioselective [2 + 2] cycloaddition of N-allenamides with cyclic N-sulfonylketimines was developed, which regioselectively occurred at the proximal CC bonds of the N-allenamides. Broad substrate scope of N-allenamides and cyclic N-sulfonylketimines was observed. A range of fused polysubstituted azetidines bearing quaternary stereocenters were afforded in good yields and...

Enantioselective [2 + 2] cycloaddition of N-allenamides with cyclic N-sulfonylketimines: access to polysubstituted azetidines bearing quaternary stereocenters† †Electronic supplementary information (ESI) available: Experimental procedure, characterization data for all the new compounds, and chiral HPLC spectra for the products. CCDC 1495550. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc05450a Click here for additional data file. Click here for additional data file.

A Ni(ClO4)2-catalyzed enantioselective [2 + 2] cycloaddition ofN-allenamides with cyclicN-sulfonylketimines was developed, which regioselectively occurred at the proximal C]C bonds of the N-allenamides. Broad substrate scope of N-allenamides and cyclic N-sulfonylketimines was observed. A range of fused polysubstituted azetidines bearing quaternary stereocenters were afforded in good yields and ...

Highly enantioselective synthesis of n,n-dialkylbenzamides with aryl-carbonyl axial chirality by rhodium-catalyzed [2+2+2] cycloaddition.

Catalytic Enantioselective Construction of All-Carbon Quaternary Stereocenters Catalytic Enantioselective Construction of All-Carbon Quaternary Stereocenters

SYNTHESIS 2006, No. 3, pp 0369–0396xx.xx.2006 Advanced online publication: 13.01.2006 DOI: 10.1055/s-2006-926302; Art ID: E14205SS © Georg Thieme Verlag Stuttgart · New York Abstract: Catalytic enantioselective construction of all-carbon quaternary stereocenters, i.e. carbon atoms bearing four different carbon substituents, poses a particular challenge in organic synthesis. This review gives a ...

Enantioselective formal [2+2] cycloaddition of ketenes with nitroso compounds catalyzed by N-heterocyclic carbenes.

Chiral N-heterocyclic carbenes were found to be efficient catalysts for the formal [2+2] cycloaddition reaction of alkyl(aryl)ketenes and nitroso compounds to give the corresponding 1,2-oxazetidin-3-ones in moderate to good yields with high enantioselectivities. Reductive ring-opening of the oxazetidinones give the corresponding α-hydroxy acid derivatives in good yields.