We herein present a facile and column-free synthetic route toward a structurally unique oxa-spirocyclic diphenol, termed as O-SPINOL. Features of the synthesis include the construction of the all-carbon quaternary center at an early stage, a key double intramolecular SAr step to introduce the spirocycles and the feasibility of operating on >100 g scale. Both enantiomers of O-SPINOL can be easily accessed through optical resolution with l-proline by control of the solvent. The chiral tridentate ligand O-SpiroPAP derived from O-SPINOL has been successfully synthesized and applied in the iridium-catalyzed asymmetric hydrogenation of bridged biaryl lactones under mild reaction conditions, providing valuable and enantioenriched axially chiral molecules in excellent yields and enantioselectivities (up to 99% yield and >99% ee). This method represents a rare example of constructing axially chiral molecules by direct reduction of esters with H.

To overcome the inherent obstacles facing the traditional surface modification of Fe3O4 magnetic nanoparticles with appropriate capping agents to anchor the catalytically active complexes, a novel retrievable copper­(II) catalyst immobilized on carboxymethyl­cellulose/Fe3O4 nanoparticles (CuII–CMC–Fe3O4) magnetic hybrid materials was successfully prepared through three steps of sequential metathesis and one step of oxidation. First, ferrous carboxymethyl­cellulose (CMC–FeII) was prepared by ionic exchange of ferrous chloride and sodium carboxymethyl­cellulose (CMC–Na). Second, the resulting CMC–FeII was treated with NaOH solution to form the corresponding hybrid material Na–CMC–Fe­(OH)2, which proceeded to be exposed to the air to afford the Na–CMC–Fe3O4. Finally, the as-prepared Na–CMC–Fe3O4 was immersed in copper sulfate solution to self-assembly-fabricate the CuII–CMC–Fe3O4 hybrid catalyst by ionic exchange of Cu­(II) with Na–CMC–Fe3O4. The morphology and structural feature of the catalyst were characterized by different microscopic and spectroscopic techniques such as FT-IR, ICP-AES, XRD, SEM, EDS, TEM, TGA, and DSC. The ensuring catalyst has been successfully applied in the CuAAC reaction of benzyl halides, sodium azide, and terminal alkynes to the synthesis of 1,2,3-triazoles. Furthermore, the CuII–CMC–Fe3O4 could be easily isolated and recovered by magnetic decantation and reused for five consecutive cycles without much loss in activity.

We herein present the design and synthesis of a structurally unique oxa-spirocyclic diphosphine ligand, termed as O-SDP. The diphosphine ligand O-SDP derived from oxa-spirocyclic diphenols (O-SPINOL) has a relatively larger bite angle compared with that of SDP, and O-SDP has been successfully applied in the ruthenium-catalyzed asymmetric hydrogenation of α,β-unsaturated carboxylic acids under mild reaction conditions. High yields and enantioselectivities were generally achieved for a wide range of substrates (up to 99% yield and >99% ee), and many of the resulting products are key intermediates of important drugs such as Sacubitril, Artemisinin, and Paroxetine.

A novel heterogeneous Cu(ii) carboxymethylcellulose catalyst was prepared and successfully employed in the A3 coupling without using any co-catalyst, other additives, bases under solvent-free conditions.

A CuH-catalyzed atropoenantioselective reduction of Bringmann’s lactones via dynamic kinetic resolution has been disclosed. This protocol features a broad substrate scope and good functional group tolerance and allows the rapid assembly of various valuable axially chiral biaryls in good to high yields (up to 92% yield) with high to excellent enantioselectivities (up to 96% ee). Moreover, this report represents a rare example that a carbonyl group of esters is reduced under homogeneous asymmetric CuH catalysis.