Copper-catalyzed reactions of α,ß-unsaturated N-tosylhydrazones with diaryliodonium salts to construct N-arylpyrazoles and diaryl sulfones.

Herein, an economical copper-catalyzed reaction of α,ß-unsaturated N-tosylhydrazones with diaryliodonium salts to construct both N-arylpyrazoles and diaryl sulfones has been developed. Both the p-toluenesulfonyl anion and the 3-arylpyrazole intermediates were formed in situ from N-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 N-arylpyrazoles under copper-catalyzed conditions. Using unsymmetrical mesityl phenyliodonium salts as substrates, mesityl p-toluenesulfide was obtained as the major product. This reaction took full advantage of the "waste" part of substrates to form an extra diaryl sulfone.

Synthesis, Characterization of Spirocyclic λ3 -Iodanes and Their Application to Prepare 4,1-Benzoxazepine-2,5-diones and 1,3-Diynes.

Herein, a [3+2] cycloaddition of aza-oxyallylic cations with ethynylbenziodoxolones for synthesis of new λ3 -iodanes containing spirocyclic 4-oxazolidinone has been developed. This cyclic λ3 -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.

A base-promoted cascade reaction of α,ß-unsaturated N-tosylhydrazones with o-hydroxybenzyl alcohols: highly regioselective synthesis of N-sec-alkylpyrazoles.

An efficient method for the synthesis of N-sec-alkylpyrazoles through a base-promoted cascade cyclization/Michael addition reaction of α,ß-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,ß-unsaturated N-tosylhydrazones and saturated N-tosylhydrazones also took place to afford pyrazoles in good yields. This reaction offers a new route to triarylmethanes with a simple operation and is applicable for large-scale synthesis.

Metal-Free Ring-Expansion Reaction of Six-membered Sulfonylimines with Diazomethanes: An Approach toward Seven-Membered Enesulfonamides.

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.

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

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.

2-[(E)-1-(4-Meth-oxy-phen-yl)pent-1-en-3-yl-idene]malononitrile.

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. Weak inter-molecular C-H⋯N hydrogen bonding is present in the crystal structure.

Trimethyl 5-(2-chloro-4-fluoro-phen-yl)-2-phenyl-pyrrolidine-2,3,4-tricarboxyl-ate.

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)°. Weak inter-molecular C-H⋯O hydrogen bonding is present in the crystal structure. One methyl group is disordered over two positions with a site-occupancy ratio of 0.651 (12):0.349 (12).

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

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 [62.50 (9) and 62.67 (9)°]. Inter-molecualar N-H⋯O and C-H⋯O hydrogen bonding is present in the crystal structure.

2-(7-Methyl-3-oxo-1-phenyl-perhydro-naphthalen-4a-yl)malononitrile.

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.

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

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)°. There is a weak intra-molecular N-H⋯O bond, which may help to establish the conformation. In the crystal, the mol-ecules are linked into a chain parallel to the b axis through inter-molecular N-H⋯O hydrogen bonds.

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

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 65.18 (9)°, respectively, with the naphthalene ring system and the benzene ring. Inter-molecular N-H⋯O and C-H⋯O hydrogen bonding is present in the crystal structure.

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

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)°.

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

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)°. Inter-molecular N-H⋯O and C-H⋯O hydrogen bonding is present in the crystal structure.

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

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 60.5 (2) and 77.92 (19)° with the two benzene rings; in the other mol-ecule, the values are 61.0 (2) and 81.43 (19)°. Inter-molecular N-H⋯O and C-H⋯O hydrogen bonding is present in the crystal structure.

Enantioselective [4 + 2] cycloaddition of cyclic N-sulfimines and acyclic enones or ynones: a concise route to sulfamidate-fused 2,6-disubstituted piperidin-4-ones.

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.

One-pot synthesis of optically enriched 2-piperidinones from aliphatic aldehydes and cyanoacrylamides.

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.