Meirong Huang

Nonlinear effects (NLEs) serve as a widespread tool in the study of asymmetric catalytic reactions. However, due to the diversity in ligand-metal coordination modes, the information obtained solely from the linear relationship between the ee values of ligands and products in complex systems is often indirect. Here, we report a precise method that directly connects the relationship between the ee values of metal complexes and products, with the purpose of determining the active species that occur in complex systems. Through an in-depth analysis of the mechanism of our previous copper-catalyzed asymmetric esterification reactions, we find an intrinsic linear relationship between the ee values of the key active metal complex (LLCu^I) and products within this traditionally non-linear system. This method holds promise as a powerful tool for the exploration of asymmetric catalysis mechanisms, heralding new avenues in the understanding and application of catalytic processes.

Herein, we describe experimental and computational studies to understand the features of oxycyanopyridinium ylides generated in situ from oxy-cyanopyridines and rhodium carbene. This chemistry has enabled the concomitant formation of both C-N and C-C bonds, providing a complementary approach for cyanation reactions. Density functional theory calculations indicate the sequential metal-bound ylide formation, rhodium-associated five-membered transition state, and 1,4-cyano group relocation. Moreover, the enantioselective rearrangement has been realized by using chiral dirhodium complexes as the catalysts.

Molecular rearrangement via carbene transfer is a powerful tool to access molecular diversity. Herein, we describe an efficient approach to selective pyridyl/aryl relocation via a rhodium-catalyzed aminoarylation of diazo compounds, providing a promising strategy to access ortho-pyridyl N-alkylated pyridone scaffolds in a single operation. This reaction features the novel reactivity of oxy-pyridinium ylide, rhodium-associated five-membered transition state, and 1,4-pyridyl/aryl relocation. A computational study discloses the initial oxy-pyridinium ylide formation, keto-enol tautomerization, and 1,4-pyridyl migration to complete the whole rearrangement.

We report here the use of pyridin-2-yl benzenesulfonates as sulfonylation reagents in a difunctionalization reaction based on oxy-pyridinium ylide chemistry, providing an effective protocol for the installation of both a sulfonyl group and a pyridone moiety into one molecule. Density functional theory (DFT) calculations disclose that the reaction process might proceed through sequential metal-bound ylide formation, keto-enol tautomerism, and the migratory rearrangement of the sulfonyl group.

An enantioselective insertion of a carbene into the Csp²–H bond of anisole derivatives has been accomplished using an achiral gold complex and a chiral phosphoric acid as the catalytic system, providing a novel protocol for the synthesis of chiral α,α-diaryl acetates. Density functional theory calculations reveal the reactivity and the origin of the enantioselectivity of this reaction.

Systematic investigation of various homoallylamines reveals N-p-methoxybenzyl homoallylamine as the optimal 2-aza-Cope reaction moiety for development of highly efficient formaldehyde fluorescent probes for in vitro and in vivo imaging.