Strategies toward High‐Loading Lithium–Sulfur Battery

Aziridines activated by N-acylation are opened to the higher substituted radical through electron transfer from titanocene(III) complexes in a novel catalytic reaction. This reaction is applicable in conjugate additions, reductions, and cyclizations and suited for the construction of quaternary carbon centers. The concerted mechanism of the ring opening is indicated by DFT calculations.

Titanocene-Catalyzed Radical Opening of N-Acylated Aziridines

Low-Valent Titanium-Mediated Radical Conjugate Addition Using Benzyl Alcohols as Benzyl Radical Sources

A catalytic system for titanocene-catalyzed epoxide hydrosilylation is described. It features a straightforward preparation of titanocene hydrides that leads to a reaction with low catalyst loading, high yields, and high selectivity of radical reduction. The mechanism was studied by a suite of methods, including kinetic studies, EPR spectroscopy, and computational methods. An unusual resting state leads to the observation of an inverse rate order with respect to the epoxide.

Highly Active Titanocene Catalysts for Epoxide Hydrosilylation: Synthesis, Theory, Kinetics, EPR Spectroscopy.

We describe a regiodivergent epoxide opening (REO) featuring a catalyst-controlled synthesis of enantiomerically and diastereomerically highly enriched or pure syn- and anti- 1,3- and 1,4-difunctionalized building blocks from a common epoxide precursor. The REO is attractive for natural product synthesis and as a branching reaction for diversity-oriented synthesis with epoxides.

General, Highly Selective Synthesis of 1,3- and 1,4-Difunctionalized Building Blocks by Regiodivergent Epoxide Opening

Zeolite-encapsulated metal clusters have been shown to be an effective bifunctional catalyst for tandem catalysis. Nevertheless, the efficient encapsulation of nanometric metal species into a high-aluminum ZSM-5 zeolite still poses a significant challenge. In this contribution, we have prepared well-dispersed and ultra-small Ru clusters encapsulated within a high-aluminum ZSM-5 zeolite (with a Si/Al ratio of ∼30–40) via an in situ two-stage hydrothermal synthesis method. Small Ru clusters with an average size of ∼1 nm have been identified by scanning transmission electron microscopy and hydrogen chemisorption. Shape-selective hydrogenation experiments with different probe molecules reveal a predominant encapsulation (∼90%) of metal clusters within the MFI zeolite cavities, which significantly enhances thermal stability of metal clusters against sintering. 27Al magic angle spinning nuclear magnetic resonance and Brønsted acid site (BAS) titration experiments show the successful incorporation of aluminum species (>99%) into the zeolite framework and build-up of intimacy between the Ru clusters and BASs at a sub-nanometric level. The resulting Ru@H-ZSM-5 shows an enhanced activity and stability for the crucial hydrodeoxygenation (HDO) of phenol to cyclohexane, in biomass valorization. This synthesis strategy could be of great help for the rational design and development of zeolitic bifunctional catalysts and could be extended to other crystalline porous materials. 

Enhanced Catalytic Performance through In Situ Encapsulation of Ultrafine Ru Clusters within a High-Aluminum Zeolite

An umpolung Mannich-type reaction of secondary amides, aliphatic aldehydes, and electrophilic alkenes has been disclosed. This reaction features the one-pot formation of C-N and C-C bonds by a titanocene-catalyzed radical coupling of the condensation products, from secondary amides and aldehydes, with electrophilic alkenes. N-substituted γ-amido-acid derivatives and γ-amido ketones can be efficiently prepared by the current method. Extension to the reaction between ketoamides and electrophilic alkenes allows rapid assembly of piperidine skeletons with α-amino quaternary carbon centers. Its synthetic utility has been demonstrated by a facile construction of the tricyclic core of marine alkaloids such as cylindricine C and polycitorol A.

Jiang He

Papers

Enhanced Catalytic Performance through In Situ Encapsulation of Ultrafine Ru Clusters within a High-Aluminum Zeolite

Titanocene(III)-Catalyzed Three-Component Reaction of Secondary Amides, Aldehydes, and Electrophilic Alkenes.

High-density catalytic heterostructures strung by buried-in carbon tube network as monolithic holey host for endurable Li-S batteries

A durable Ni/La-Y catalyst for efficient hydrogenation of γ-valerolactone into pentanoic biofuels

Titanocene(III)-Catalyzed Three-Component Reaction of Secondary Amides, Aldehydes, and Electrophilic Alkenes.