Studies on Hydroiodination and Deconjugation of 5—Aryloxy—（thiophenyl）—3—pentyn—2—one

One-pot hydroiodination and deconjugation of 5-aryloxy(or thiophenyl)-3-pentyn-2-one with a reagent system of sodium iodide/trimethylsilyl chloride/water in acetonitrile at 25℃ have been described.The plasuible mechanism was discussed.The reaction provided a simple and useful method for the preparation of (Z)-β-substituted β，γ-enones and (Z)-β-substituted α，β-unsaturated ketones.     

New Preparation of (Z)-1-Phenyl-3-cyano-2-propen-1-ones

Reaction of γ-phenyl-β,γ-unsaturated hydroxamates with bis(collidine)bromine(I) hexafluorophosphate led to the formation of cyclic bromo imidates. Reaction of these with triethylamine led to the formation of 3-cyano-2-propen-1-ones with good yields by a fragmentation reaction.     

Dual Catalysis with Copper and Rhenium for Trifluoromethylation of Propargylic Alcohols: Efficient Synthesis of α‐Trifluoromethylated Enones

Trifluoromethylation of propargylic alcohols to provide (Z)‐α‐trifluoromethylated enones and β‐unsubstituted α‐trifluoromethylated enones proceeded with high yield and selectivity in the presence of CuI/Re₂O₇. The Z isomer was formed under kinetic control, though it is less stable than the E isomer in terms of steric repulsion.     

The Cu-catalyzed asymmetric conjugate addition with chiral diphosphite ligands derived from D-(-)-tartaric acid

A series of diphosphite ligands, which were derived from D-(-)-tartaric acid, have been synthesized and successfully applied in the Cu-catalyzed asymmetric conjugate addition of organozincs to enones. There was a synergic effect between the stereogenic centers of the D-(-)-tartaric acid skeleton and the axially H₈-binaphthyl moieties of ligand 2c. And ligand 2c shows a comparative catalytic performance to ligand 1-N-benzylpyrrolidine-3,4-bis[(S)-1,1′-H₈-binaphthyl-2,2′-diyl]phosphite-L-tartaric acid1d derived from L-(+)-tartaric acid. Therefore, for cyclic enones, both enantiomers of the addition products can be obtained in high enantioselectivity (ees up to 96%) by simply selecting ligands 1d or 2c derived from D-(-)-tartaric acid or L-(+)-tartaric acid. Moreover, the sense of enantiodiscrimination of the products was mainly determined by the configuration of the binaphthyl phosphite moieties.     

Diastereoselectivity-Switchable Gold-Catalyzed Formal [3+2]-Cycloadditions of N-2,2,2-Trifluoroethylisatin Ketimines with Yne−Enones

The unexpected gold-catalyzed formal [3+2]-cycloaddition of N-2,2,2-trifluoroethylisatin ketimines with 2-(1-Alkynyl)-2-alken-1-ones is reported. Both diastereomers of the corresponding cycloadducts were formed in moderate to excellent yields with excellent diastereoselectivities by switching the catalytic system from mono-gold to gold/silver bimetallic catalytic system. The practicality of this protocol is demonstrated by scale-up reaction and the transformations of the cycloadduct.     

Polyene Cyclization Promoted by the Cross Conjugated α-Carbalkoxy Enone System. An Efficient Approach to Highly Functionalized Decalins

The cross conjugated α-carbalkoxy enone system was found to be an excellent promoter for polyene cyclization. Under mild conditions, the reaction occurred readily with a high degree of regio- and stereoselectivity. Based on this facile process, an efficient method for the construction of highly functionalized decalin derivatives has been developed.     

Efficient Synthesis of 3-Aryl-5-chloroindan-1-ones via Free Radical–Mediated Intramolecular Cyclization

An efficient free radical–mediated intramolecular cyclization strategy has been developed for the synthesis of 3-aryl-5-chloroindan-1-ones. Variously substituted 2,4-dichloroenones afforded 3-aryl-5-chloroindan-1-ones in quantitative yields upon intramolecular cyclization under free radical conditions.     

Microwave-Induced Aza-Michael Reaction in Water: A Remarkably Simple Procedure

Microwave-induced fast addition of several amines to conjugated carbonyl compounds has been carried out in water very efficiently in the absence of any catalyst.     

Free Radical–Mediated Chemoselective Reduction of Enones

A novel methodology has been devised for the chemoselective reduction of enones involving the use of ⁿ Bu₃SnH and azobisisobutyronitrile. The 1,4-reduction of variously substituted α,β-unsaturated cyclic and acyclic enones has been successfully carried out under free radical reaction conditions. The reaction has been determined to proceed via single-electron transfer.

[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications^® for the following free supplemental resource(s): Full experimental and spectral details.]     

Organocatalytic (1+4)-Annulations of MBH Adducts with Electron-Deficient Systems

Benefited from the rapid development of MBH reaction, the reaction of MBH adducts have been established as the most synthetically useful transformations. However, compared with the well-established allylic alkylations and (3+2)-annulations, the (1+4)-annulations of MBH adducts have not developed rapidly until recently. As a helpful complement to the (3+2)-annulations of MBH adducts, the (1+4)-annulations of MBH adducts opens a robust access to structurally diverse five-membered carbo- and heterocycles. This paper summarizes recent advances in organocatalytic (1+4)-annulations using MBH adducts as 1 C-synthons for the construction of functionalized five-membered carbo- and heterocycles.