Brønsted Acid Catalyzed Cycloisomerizations of 5,2-Enyne-1-ones: Highly Regioselective Synthesis of 2,3-Dihydro-4H-pyran-4-ones

Highly efficient mesoporous polymer supported phosphine-gold(i) complex catalysts for amination of allylic alcohols and intramolecular cyclization reactions

A series of novel heterogeneous gold(i) catalysts were synthesized by immobilizing gold(i) complexes on ordered mesoporous polymer FDU-15 and characterized by XRD, N₂ adsorption–desorption, FT-IR, TEM, EDS, etc. The catalytic activities of these catalysts were evaluated by the amination reactions of allylic alcohols. Among the catalysts investigated, FDU-(p-CF₃Ph)₂PAuCl (3d) was identified as the most efficient catalyst. Compared to the homogeneous catalyst, the enhanced catalytic activity of the heterogeneous gold(i) catalyst is closely related to the mesoporous structure of FDU-15. The catalytic system was suitable for a broad range of substrates and can be easily recovered and recycled at least twelve times without significant loss of catalytic activity. In addition, the catalytic performance of 3d was further examined for intramolecular cyclization for the synthesis of heterocyclic compounds.

Preparation of highly ordered mesoporous polymer supported gold(i) catalyst as efficient and recyclable catalysts for construction of carbon–hetero bond.

Rhodium/Silver Synergistic Catalysis in Highly Enantioselective Cycloisomerization/Cross Coupling of Keto-Vinylidenecyclopropanes with Terminal Alkynes

A rhodium/silver synergistic catalysis has been established, enabling cycloisomerization/cross coupling of keto-vinylidenecyclopropanes (VDCPs) with terminal alkynes toward the regio- and enantioselective formation of diversified tetrahydropyridin-3-ol tethered 1,4-enynes in good yields and high ee values. In this synergistic catalysis, Rh(I) and Ag(I) catalysts selectively activate keto-VDCP substrates and terminal alkynes to generate the π-allyl Rh(III) complex of oxa-rhodacyclic intermediate and Ag alkynyl intermediate, respectively. The rapid transmetalation of alkynyl groups from Ag to Rh is proposed to play a key role in realizing the regioselective cleavage of the distal bond of the three-membered ring in this transformation.

Atom-Economic Synthesis of 4-Pyrones from Diynones and Water

Transition-metal-free synthesis of 4-pyrones via TfOH-promoted nucleophilic addition/cyclization of diynones and water has been developed. This transformation is simple, atom economical and environmentally benign, providing rapid and efficient access to substituted 4-pyrones.

Chemo- and regioselective reductive deoxygenation of 1-en-4-yn-ols into 1,4-enynes through FeF3 and TfOH co-catalysis

We report chemo- and regioselective direct reductive deoxygenation of 1-en-4-yn-3-ols into 1,4-enynes through FeF₃ and TfOH cooperative catalysis under NBSH-mediated conditions.

Simple access to 5-carboalkoxy-2,3-dihydro-4H-pyran-4-ones via domino acylative electrocyclization: the first three step total synthesis of the dihydronaphthopyran-4-one class of natural products

5-Carboalkoxy-2,3-dihydropyran-4-ones synthesised via domino C-acylation/6π-oxaelectrocyclization protocol was employed as a starting material for the first three step total synthesis of dihydronaphthopyran-4-one class of natural products.