Xiao-Long Zhang

Enantioselective synthesis of functionalized 3,4-disubstituted dihydro-2(1H)-quinolinones via Michael–hemiaminalization/oxidation reaction

A novel method is developed for the enantioselective synthesis of highly functionalized 3,4-disubstituted dihydro-2(1H)-quinolinones bearing two trans contiguous stereogenic centers with excellent diastereoselectivities (up to >99 : 1 dr) and high to excellent enantioselectivities (up to >99% ee). The process combines an enantioselective organocatalytic Michael–hemiaminalization reaction and a highly efficient oxidation reaction sequence with good yields and stereoselectivity.

Synthesis and Crystal Structure Characterization of (1R,3S,4S,5S,6S,7R,8S)-8-(4-chlorophenyl)-3-hydroxy-7-methyl-6-nitro-N,5-diphenyl-2-oxabicyclo-[2.2.2]octane-1-carboxamide

The title compound, (1R,3S,4S,5S,6S,7R,8S)-8-(4-chlorophenyl)-3-hydroxy-7-methyl-6-nitro-N,5- diphenyl-2-oxabicyclo[2.2.2]octane-1-carboxamide-5, was synthesized and characterized by 1H, 13C NMR and HRMS spectroscopy. Its absolute molecular configuration was investigated by X-ray crystallography. Compound 5 co-crystallizes with methanol in the orthorhombic space group P 21 21 21 with cell parameters of a = 10.896(2) Å, b = 14.575(3) Å, c = 16.414(3) Å, V = 2606.7(9) Å3, and Z = 4. The crystal structure analysis revealed that the structure exhibits intermolecular hydrogen bonds of the types O-H…O, N-H…O, C-H…O.

Synthesis and Crystal Structure Characterization of (1R,2R,3R,5S)-3-(3-chlorophenyl)-1-hydroxy-2-methyl-6-phenyl-8-oxa-6-azabicyclo[3.2.1]octan-7-one

The title compound, (1R,2R,3R,5S)-3-(3-chlorophenyl)-1-hydroxy-2-methyl-6-phenyl-8-oxa-6-azabicyclo[3.2.1]octan-7-one, was synthesized and characterized by 1H and 13C NMR and HRMS spectroscopy. Its absolute molecular configuration was investigated by X-ray crystallography. The crystal structure analysis revealed that the structure exhibits intermolecular hydrogen bonds of the type O‒H…O. The methyl group and chlorophenyl group are located in the cis configuration. The conformation is stabilized by weak intermolecular C‒H... O interactions.