Publications by authors named "Lian-Mei Chen"

Herein, an economical copper-catalyzed reaction of α,β-unsaturated -tosylhydrazones with diaryliodonium salts to construct both -arylpyrazoles and diaryl sulfones has been developed. Both the -toluenesulfonyl anion and the 3-arylpyrazole intermediates were formed from -tosylhydrazones. Subsequently, the former reacted rapidly with diaryliodonium salts to give diaryl sulfones and aryl iodide intermediates, and the latter reacted with aryl iodide to give -arylpyrazoles under copper-catalyzed conditions.

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Herein, a [3+2] cycloaddition of aza-oxyallylic cations with ethynylbenziodoxolones for synthesis of new λ -iodanes containing spirocyclic 4-oxazolidinone has been developed. This cyclic λ -iodanes display stability in air and excellent solubility in organic solvent. Using them as substrate, both the 4,1-benzoxazepine-2,5-diones and symmetrical 1,3-diynes derivatives were afforded in high yield under copper(I)-catalyzed conditions.

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An efficient method for the synthesis of N-sec-alkylpyrazoles through a base-promoted cascade cyclization/Michael addition reaction of α,β-unsaturated N-tosylhydrazones with ortho-hydroxybenzyl alcohols has been developed. The desired products containing di- or triaryl groups at the same carbon atom were afforded in good to excellent yields with excellent regioselectivities (>20 : 1). Moreover, a three-component reaction of ortho-hydroxybenzyl alcohols, α,β-unsaturated N-tosylhydrazones and saturated N-tosylhydrazones also took place to afford pyrazoles in good yields.

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A new metal-free, ring-expansion reaction of six-membered N-sulfonylimines with unstable diazomethanes, generated in situ from the N-tosylhydrazones, has been developed. This reaction delivers valuable seven-membered enesulfonamides by a Tiffeneau-Demjanov rearrangement and intramolecular proton transfer tautomerization process. Moreover, this ring-expansion reaction can be carried out in a one-pot fashion and scaled up to the gram scale by using aryl aldehydes, without the need to isolate the N-tosylhydrazone.

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A concise route to valuable sulfamate-fused 2,6-disubstituted piperidin-4-ones or 2,3-dihydropyridin-4(1H)-ones in good yield with high diastereo- and enantioselectivity is presented. The combination of chiral primary amine and o-fluorobenzoic acid efficiently promoted an asymmetric [4 + 2] cycloaddition reaction of N-sulfonylimines and enones or ynones. The cycloaddition reaction between cyclic N-sulfonylimines and ynones is first reported.

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A highly stereoselective one-pot reaction of aliphatic aldehydes and cyanoacrylamides has been developed. The one-pot reaction includes an organocatalytic Michael addition followed by an intramolecular hemiaminalization. After reduction, optically enriched 2-piperidinones with three contiguous chiral centers were obtained in up to 95% yield and 9:1 dr with 99% ee.

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In the title compound, C(15)H(14)N(2)O, the mol-ecule skeleton displays an approximately planar structure except for the ethyl group [maximum deviation = 0.042 (1) Å]. The meth-oxy-phenyl ring and butanylidenemalononitrile groups are located on opposite sides of the C=C bond, showing an E configuration.

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(E)-N-Benzyl-2-cyano-3-phenyl-acryl-amide.

Acta Crystallogr Sect E Struct Rep Online

December 2010

In the title compound, C(17)H(14)N(2)O, the N-benzyl-formamide and phenyl groups are located on the opposite sides of the C=C bond, showing an E configuration; the terminal phenyl rings are twisted to each other at a dihedral angle of 63.61 (7)°. Inter-molecular classical N-H⋯N and weak C-H⋯O hydrogen bonds occur in the crystal structure.

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(E)-2-(1,3-Diphenyl-allyl-idene)malononitrile.

Acta Crystallogr Sect E Struct Rep Online

November 2009

The title compound, C(18)H(12)N(2), adopts an E conformation with the benzyl-idenemalononitrile and phenyl groups located on opposite sides of the C=C bond. The two phenyl rings are oriented at a dihedral angle of 62.49 (7)°.

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3-(1-Naphth-yl)-N-phenyl-oxirane-2-carboxamide.

Acta Crystallogr Sect E Struct Rep Online

November 2009

In the title compound, C(19)H(15)NO(2), the mol-ecule adopts a syn configuration with the naphthalene and N-phenyl-formamide units located on the same side of the ep-oxy ring. The ep-oxy ring makes dihedral angles of 58.73 (9) and 65.

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(2R,3R)-3-(2-Chloro-phen-yl)-N-phenyl-oxirane-2-carboxamide.

Acta Crystallogr Sect E Struct Rep Online

November 2009

In the title compound, C(15)H(12)ClNO(2), the two benzene rings adopt a syn configuration with respect to the ep-oxy ring; the dihedral angles between the ep-oxy ring and the two benzene rings are 59.71 (16) and 67.58 (15)°.

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In the title compound, C(20)H(22)N(2)O, both cyclo-hexane rings adopt chair conformations. Weak C-H⋯N and C-H⋯O hydrogen bonding is present in the crystal structure.

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3-(3-Bromo-phen-yl)-N-phenyl-oxirane-2-carboxamide.

Acta Crystallogr Sect E Struct Rep Online

November 2009

There are two independent mol-ecules in the asymmetric unit of the title compound, C(15)H(12)BrNO(2). In both mol-ecules, the two benzene rings adopt a cis configuration with respect to the ep-oxy ring. In one mol-ecule, the ep-oxy ring makes dihedral angles of 60.

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3-(2-Bromo-phen-yl)-N-phenyl-oxirane-2-carboxamide.

Acta Crystallogr Sect E Struct Rep Online

November 2009

In the mol-ecule of the title compound, C(15)H(12)BrNO(2), the two benzene rings adopt a syn configuration with respect to the ep-oxy ring; the dihedral angles between the ep-oxy ring and the two benzene rings are 59.90 (13) and 68.01 (12)°.

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3-(3-Chloro-phen-yl)-N-phenyl-oxirane-2-carboxamide.

Acta Crystallogr Sect E Struct Rep Online

November 2009

There are two independent mol-ecules in the asymmetric unit of the title compound, C(15)H(12)ClN(2)O(2). In each mol-ecule, the two benzene rings adopt a cis configuration with respect to the ep-oxy ring. The dihedral angles between the ep-oxy ring and chloro-phenyl rings are essentially identical in the two mol-ecules [62.

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The title compound, C(22)H(21)ClFNO(6), was synthesized by the 1,3-dipolar cyclo-addition reaction of dimethyl maleate, methyl 2-amino-2-phenyl-acetate and 2-chloro-4-fluoro-benzaldehyde. The pyrrolidine ring possesses an envelope conformation and the two benzene rings are oriented at a dihedral angle of 68.28 (7)°.

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