Modular Dual-Tasked C-H Methylation via the Catellani Strategy

We report a dual-tasked methylation that is based on cooperative palladium/norbornene catalysis. Readily available (hetero)aryl halides (39 iodides and 4 bromides) and inexpensive MeOTs or trimethylphosphate are utilized as the substrates and methylating reagent, respectively. Six types of "ipso" terminations can modularly couple with this "ortho" C-H methylation to constitute a versatile methylation toolbox for preparing diversified methylated arenes. This toolbox features inexpensive methyl sources, excellent functional-group tolerance, simple reaction procedures, and scalability. Importantly, it can be uneventfully extended to isotope-labeled methylation by switching to the corresponding reagents CD₃OTs or ¹³CH₃OTs. Moreover, this toolbox can be applied to late-stage modification of biorelevant substrates with complete stereoretention. We believe these salient and practical features of our dual-tasked methylation toolbox will be welcomed by academic and industrial researchers.

Chemoselective Borono-Catellani Arylation for Unsymmetrical Biaryls Synthesis

Reported is the borono-Catellani arylation process for unsymmetrical biaryls synthesis, utilizing the readily available pinacol ester of arylboronic acids, aryl bromides, and olefins as the reactants. The distinct reactivity of arylboronic ester and aryl bromides secures the excellent chemoselectivity in the pivotal arylation step. The reaction is enabled by the cooperative catalysis of Pd(OAc)₂ and the NBE derivative N⁷, with molecular oxygen as the terminal oxidant.

Catalytic asymmetric synthesis of tetrahydrocarbazoles

This feature article summarises recent advances in catalytic asymmetric synthesis of THCs, with emphases on reaction type and reaction mechanism.

A palladium/norbornene cooperative catalysis to access N-containing bridged scaffolds

A palladium/norbornene cooperative catalysis promoted annulation involving an ortho-C-H amination and intramolecular Heck cascade between aryl iodides and functionalized amination reagents is reported, thereby providing a highly convergent access to the unique N-containing bridged scaffolds: hexahydro-2,6-methano-1-benzazocine. The salient features of the reaction include its broad substrate scope (with respect to aryl iodides), its high step economy, and good chemoselectivity. Preliminary studies underscore the future promise of rendering this Catellani-type annulation enantioselective.

Alkylating Reagents Employed in Catellani-Type Reactions

The Catellani reaction is a powerful strategy that allows the expeditious synthesis of highly substituted arenes, which are not easily accessible through traditional transition-metal-catalyzed cross-coupling reactions. This reaction utilizes the synergistic interplay of palladium and norbornene catalysis to facilitate sequential ortho-C-H functionalization and ipso termination of aryl iodides in a single operation. Since pioneering work by the group of Catellani in 1997, and later by the group of Lautens, this chemistry has attracted considerable attention from the synthetic chemistry community. Dramatic progress has been made by a number of groups in the past two decades. In this Minireview, the alkylating reagents employed in this intriguing reaction and the corresponding applications in organic synthesis are summarized; thus complementing existing reviews to inspire future developments.

Modular One-Step Three-Component Synthesis of Tetrahydroisoquinolines Using a Catellani Strategy

Reported is a modular one-step three-component synthesis of tetrahydroisoquinolines using a Catellani strategy. This process exploits aziridines as the alkylating reagents, through palladium/norbornene cooperative catalysis, to enable a Catellani/Heck/aza-Michael addition cascade. This mild, chemoselective, and scalable protocol has broad substrate scope (43 examples, up to 90 % yield). The most striking feature of this protocol is the excellent regioselectivity and diastereoselectivity observed for 2-alkyl- and 2-aryl-substituted aziridines to access 1,3-cis-substituted and 1,4-cis-substituted tetrahydroisoquinolines, respectively. Moreover, this is a versatile process with high step and atom economy.

The Discovery of a Palladium(II)-Initiated Borono-Catellani Reaction

Reported is a novel palladium(II)-initiated Catellani-type reaction that utilizes widely accessible aryl boronic acids as the substrates instead of aryl halides, thereby greatly expanding the existing scope of this powerful transformation. This borono-Catellani reaction was promoted by cooperative catalysis between Pd(OAc)₂ and the inexpensive 5-norbornene-2-carbonitrile. Practicality is the striking feature of the reaction: it is run open to air at ambient temperature and no phosphine ligand is needed. This mild, chemoselective, and scalable protocol is compatible with a large range of readily available functionalized aryl boronic acids and bromides, as well as terminating olefins (50 examples, 39-97 % yields). Moreover, the orthogonal reactivity between the borono-Catellani and classical Catellani reaction was demonstrated. This work is expected to open new avenues for developing novel Catellani-type reactions.

Epoxides as Alkylating Reagents for the Catellani Reaction

We report a cooperative catalytic system comprising a Pd^II complex, XPhos, and the potassium salt of 5-norbornene-2-carboxylic acid that enables the use of epoxides as alkylating reagents in the Catellani reaction, thereby expanding the existing paradigm of this powerful transformation. The potassium salt of inexpensive 5-norbornene-2-carboxylic acid acts as both mediator and base in the process. This mild, chemoselective, scalable, and atom-economical protocol is compatible with a wide variety of readily available functionalized aryl iodides and epoxides, as well as terminating olefins. The resulting products undergo facile oxa-Michael addition to furnish ubiquitous isochroman scaffolds.

Convergent syntheses of 2,3-dihydrobenzofurans via a Catellani strategy

The annulation of aryl iodides and epoxides to convergently access valuable 2,3-dihydrobenzofuran scaffolds was developed via a Catellani strategy.

Co-occurrence of DSM-IV mental disorders and alcohol use disorder among adult Chinese males

BACKGROUND

Studies from high-income countries report moderate-to-strong positive associations between alcohol use disorder (AUD) and other mental disorders, but there is little evidence about the comorbidity of AUD from low-and-middle-income countries.

METHODS

A sample of 74 752 adults from five provinces that account for >12% of China's adult population was screened using the General Health Questionnaire, and the Structured Clinical Interview for DSM-IV was administered by psychiatrists to a subsample of 9619 males. The associations between AUD and other mental disorders at each site and the characteristics of men with AUD with and without comorbid mental disorders were estimated using logistic regression and summarized across sites using meta-analysis. Generalized estimation equations estimated the associations between the clinical features of alcohol dependence and comorbidity.

RESULTS

Robust inverse associations were found between current AUD and any mood disorder (adjusted OR = 0.6, 95% CI = 0.4-0.8) and any anxiety disorder (OR = 0.5, 95% CI = 0.3-1.0). Compared with men without AUD, men with AUD without comorbid disorders were more likely to be middle-aged, to be currently married, and to have higher family incomes. Men with comorbid AUD and other disorders were more likely to have the clinical features of alcohol dependence than men with AUD without comorbid disorders.

CONCLUSIONS

Inverse associations between AUD and other mental disorders and the higher social status of men with AUD than men without AUD found in this large, representative sample of community-dwelling Chinese males highlight the importance of considering the local substance-use culture when designing clinical or preventive interventions for addictive conditions.

Integration of aerobic oxidation and intramolecular asymmetric aza-Friedel-Crafts reactions with a chiral bifunctional heterogeneous catalyst

A new class of chiral bifunctional heterogeneous materials composed of Au/Pd nanoparticles and chiral phosphoric acids as active orthogonal catalysts was prepared by utilizing a facile pseudo-suspension co-polymerization method. It was found that this heterogeneous catalyst was capable of facilitating the sequential aerobic oxidation-asymmetric intramolecular aza-Friedel-Crafts reaction between benzyl alcohols and N-aminoethylpyrroles. Moreover, the designed chiral heterogeneous catalyst could be recovered and reused several times without significant loss of activity or enantioselectivity.

Palladium/sulfoxide–phosphine-catalyzed highly enantioselective allylic etherification and amination

Pd-catalyzed asymmetric allylic etherification and amination with a wide range of O- and N-nucleophiles using a chiral sulfoxide–phosphine ligand have been developed (up to 97% yield, 98.5% ee).

Rational design of sulfoxide–phosphine ligands for Pd-catalyzed enantioselective allylic alkylation reactions

A new type of chiral sulfoxide–phosphine ligands have been developed by a rational combination of two privileged scaffolds and successfully applied to Pd-catalyzed enantioselective allylic alkylation reactions.