Through the joint forces of computation and experiment, detailed mechanism Lu phosphine catalyzed (3 + 2) cycloaddition allenoates alkenes has been elucidated. The overall potential energy surface reaction computed. More importantly, theory experiment have confirmed that a trace amount water plays critical role in assisting process [1,2] proton shift reaction.

Asymmetric hydrogenation of quinolines catalyzed by chiral cationic η(6)-arene-N-tosylethylenediamine-Ru(II) complexes have been investigated. A wide range quinoline derivatives, including 2-alkylquinolines, 2-arylquinolines, and 2-functionalized 2,3-disubstituted were efficiently hydrogenated to give 1,2,3,4-tetrahydroquinolines with up >99% ee full conversions. This catalytic protocol is applicable the gram-scale synthesis some biologically active tetrahydroquinolines, such as...

Abstract With the aid of computations and experiments, detailed mechanism phosphine‐catalyzed [3+2] cycloaddition reactions allenoates electron‐deficient alkenes has been investigated. It was found that this reaction includes four consecutive processes: 1) In situ generation a 1,3‐dipole from allenoate phosphine, 2) stepwise cycloaddition, 3) water‐catalyzed [1,2]‐hydrogen shift, 4) elimination phosphine catalyst. is key to all nucleophilic reactions. Through kinetic study we have shown...

Polyurethanes (PUs) have many applications resulting from their preeminent properties, but being commonly used toxic catalysts, and the lack of processability for PU thermosets cause limitations. Herein, we report a new class PU-like dynamic covalent polymers, poly(oxime-urethanes) (POUs), which are prepared uncatalyzed polyaddition multifunctional oximes hexamethylene diisocyanate (HDI) at ambient temperature. Kinetics studies reveal that almost complete polymerization (∼99% conversion) can...

Vinylcyclopropane (VCP) derivatives participate in a variety of transition-metal-catalyzed multicomponent cycloadditions to produce five- eight-membered carbocycles. Various cycloaddition modes provide novel approaches mono-, bi-, and polycyclic molecules. In this Synopsis, recent advances VCP are discussed, with particular emphasis on the influence substitution pattern modes. A tabular summary applications natural product synthesis is also presented.

Practical syntheses of natural products and their analogues with eight-membered carbocyclic skeletons are important for medicinal biological investigations. However, methods strategies to construct the carbocycles limited. Therefore, developing new synthesize is highly desired. In this Account, we describe our development three rhodium-catalyzed cycloadditions construction carbocycles, which have great potential in addressing challenges synthesis medium-sized ring systems. The first reaction...

A computational study with the Becke3LYP density functional was carried out to elucidate mechanisms of Au(I)-catalyzed reactions enynyl acetates involving tandem [3,3]-rearrangement, Nazarov reaction, and [1,2]-hydrogen shift. Calculations indicate that [3,3]-rearrangement is a two-step process activation free energies below 10 kcal/mol for both steps. The following Nazarov-type 4pi electrocyclic ring-closure reaction Au-containing dienyl cation also easy an energy 3.2 in CH2Cl2. final step...

The asymmetric O−H insertion reaction is an ideal synthetic strategy for preparing optically pure α-alkoxy, α-aryloxy, and α-hydroxy carboxylic acid derivatives, which are valuable building blocks the construction of natural products other biologically active molecules. Surprisingly, to date there have been no reports significant levels enantiocontrol in insertions using chiral dirhodium(II) catalysts, powerful C−H insertions. Only recently, through use copper highly enantioselective...

Through the combined use of computational (density functional theory) and experimental studies, a new [Rh(CO)2Cl]2 catalyzed two-component [5+2+1] cycloaddition ene-vinylcyclopropanes CO for synthesis fused bicyclic cyclooctenones has been designed experimentally realized. The key point behind this design is to turn disfavored reductive elimination (sp3)C−Rh−C(sp3) an easier migratory (sp3)C−Rh−CO−C(sp3) by introduction CO. These reactions proceed in good yields substrates with various...

Abstract Obtaining the reactivities (such as nucleophilicities and electrophilicities) of molecules is fundamental importance in chemistry. Mayr co‐workers have developed equation, which has been widely used to quantify nucleophilicity electrophilicity. Herein we propose a theoretical understanding equation based on frontier molecular orbital (FMO) theory Eyring transition state theory, showing that molecule related energy this molecule’s highest occupied (HOMO), while electrophilicity...

DFT calculations have been applied to investigate the reaction mechanism of rhodium dimer, [Rh(CO)2Cl]2, catalyzed intermolecular (5 + 2) reactions between vinylcyclopropanes and alkynes. The catalytic species is Rh(CO)Cl cycle through sequential cyclopropyl cleavage vinylcyclopropane, alkyne insertion (rate-determining step), a migratory reductive elimination.

Reported herein is a ruthenium-catalyzed formal dehydrative [4 + 2] cycloaddition of enamides and alkynes, representing mild economic protocol for the construction highly substituted pyridines. Notably, features broad substrate scope, high efficiency, good functional group tolerance, excellent regioselectivities were observed this reaction. Density theory (DFT) calculations experiments have been carried out to understand mechanism regiochemistry. DFT suggested that reaction starts with...

A tandem reaction involving a Rh(I)-catalyzed two-component [(5+2)+1] cycloaddition and an aldol condensation has been developed to construct the tricyclo[6.3.0.02,6]undecane skeleton its heteroatom-imbedded analogues. Meanwhile, this method successfully applied natural product synthesis for first time. The present strategy enables straightforward approach linear triquinane skeleton, as demonstrated by concise step economical syntheses of hirsutene 1-desoxy-hypnophilin, whereby core is...

The first highly enantioselective S–H bond insertion reaction was developed by cooperative catalysis of dirhodium(II) carboxylates and chiral spiro phosphoric acids (SPAs) under mild neutral conditions with fast rates, high yields (77–97% yields), excellent enantioselectivities (up to 98% ee). catalytic provides a efficient method for the synthesis sulfur-containing compounds advances drug (S)-Eflucimibe. A systematic 31P NMR study revealed that no ligand exchange between SPAs occurred in...

Rhodium dimer [Rh(CO)2Cl]2 efficiently catalyzes the intra- and intermolecular (5 + 2) reactions of vinylcyclopropanes with alkynes allenes, but not alkenes. This difference in reactivity is attributed to difficulty reductive elimination for alkene. The computed transition structures show that participation second π-orbital acetylene allene reduces barrier by 9∼15 kcal/mol, compared ethylene, which no such interactions are possible.

Vinylcyclopropane (VCP) has been well applied as a five-carbon component, rather than three-carbon in transition-metal catalyzed cycloadditions. Here we demonstrate Rh(I)-catalyzed [3 + 2] reaction of trans-VCP-enes, where VCP acts synthon to furnish five-membered carbocycles. This novel cycloaddition is efficient generating bicyclic cyclopentanes good yields from simple and easily prepared substrates. When cis-VCP-ene used the substrate, unit give [5 cycloadduct. Rationalization...

A highly enantioselective Rh(I)-catalyzed intramolecular [3 + 2] cycloaddition of 1-yne-VCPs to bicyclo[3.3.0] compounds with an all-carbon chiral quaternary stereocenter at the bridgehead carbon was developed. DFT calculations energy surface catalytic cycle (complexation, cyclopropane cleavage, alkyne insertion, and reductive elimination) asymmetric reaction indicated that rate- stereo-determining step is alkyne-insertion step. Analysis transition states revealed serious steric repulsion...

The first studies on the regioselectivity of Rh(I)-catalyzed (5 + 2) cycloadditions between vinylcyclopropanes (VCPs) and alkynes have been conducted experimentally analyzed using density functional theory (DFT). previously unexplored regiochemical consequences for this catalytic, intermolecular cycloaddition were determined by studying reactions several substituted VCPs with a range unsymmetrical alkynes. Experimental trends identified, predictive model was established. terminal...

A novel Rh(I)-catalyzed [(3 + 2) 1] cycloaddition, which can be regarded as a homologous Pauson−Khand reaction, was developed to synthesize bicyclic cyclohexenones and cyclohexanones, enabling new approach for synthesis of six-membered carbocycles ubiquitously found in natural products pharmaceutics. The significance the Rh-catalyzed cycloaddition has been demonstrated by total furanoid sesquiterpene product, α-agarofuran, skeleton constructed reaction 1-yne-VCP CO.

A CuI-catalyzed A(3) (amines, aldehydes and alkynes) reaction of tetrahydroisoquinolines (THIQs), aldehydes, alkynes to give C1-alkynylated THIQ products (endo-yne-THIQs) was developed. This redox neutral C1-alkynylation THIQs, which conducted under mild conditions, has a broad scope for the used alkynes. It proposed that first generates in situ exo-iminium ions, then isomerize endo-iminium ions react with copper acetylides endo alkynylated THIQs (endo-yne-THIQs).

A novel organocatalytic asymmetric tandem Nazarov cyclization/semipinacol rearrangement reaction using "unactivated" substrates has been developed, generating a series of chiral spiro[4.4]nonane-1,6-diones in up to 96% yield and 97% enantiomeric excess. Significantly, it is the first direct example for synthesis cyclopentanones with four stereocenters cyclization. DFT calculations have applied understand mechanism, stereochemistry, substituent effects.

The study of new C–H silylation reagents and reactions remains an important topic. We reported that under Rh catalysis, silacyclobutanes (SCBs) for the first time were able to react with C(sp2)–H C(sp3)–H bonds, however underlying reasons such a reactivity not understood. Through this combined computational experimental on SCBs, we only depict reaction pathway fully accounts all findings but also streamline more efficient catalyst significantly improves rates yields. Our key include: (1)...

Previously, we developed a rhodium-catalyzed [5 + 2 1] cycloaddition of ene–vinylcyclopropanes (ene–VCPs) and carbon monoxide to synthesize eight-membered carbocycles. The efficiency this reaction can be appreciated from its application in the synthesis several natural products. Herein report results 15-year investigation into mechanism by applying visual kinetic analysis high-level quantum chemical calculations at DLPNO-CCSD(T)//BMK level. According measurements, resting state catalyst...

Due to the unique effect of fluorine atoms, efficient construction high-value alkyl fluorides has attracted significant interest in modern drug development. However, enantioselective catalytic strategies for assembly highly functionalized chiral C(sp