Molecular recognition and self-assembly are often mediated by intermolecular forces involving aromatic π-systems. Despite the ubiquity of such interactions in biological systems and in the design of functional materials, the elusive nature of aromatic π interaction results in that they have been seldom used as a design element for promoting challenging chemical reactions. Described here is a well-engineered catalytic system into which non-covalent π interactions are directly incorporated. Enabled by a lone pair-π interaction and a π-π stacking interaction operating collectively, efficient chiral recognition is successfully achieved in the long-pursued dihydroxylation-based kinetic resolution. Density functional theory calculations shed light on the crucial role played by the lone pair-π interaction between the carbonyl oxygen of the cinchona alkaloid ligand and the electron-deficient phthalazine π moiety of the substrate in the stereoselectivity-determining transition states. This discovery serves as a proof-of-principle example showing how the weak non-covalent π interactions, if ingeniously designed, could be a powerful guide in attaining highly enantioselective catalysis.
The first example of the palladium-catalyzed, three-component tandem reaction of 2-aminobenzonitriles, aldehydes, and arylboronic acids has been developed, providing a new approach for one-pot assembly of diverse quinazolines in moderate to good yields. A noteworthy feature of this method is the tolerance of bromo and iodo groups, which affords versatility for further synthetic manipulations. Preliminary mechanistic experiments indicate that this tandem process involves two possible mechanistic pathways for the formation of quinazolines via catalytic carbopalladation of the cyano group.
The first example of the Pd-catalyzed addition of organoboron
reagents
to dinitriles, as an efficient means of preparing 2,5-diarylpyrroles
and 2,6-diarylpyridines, has been discussed here. Furthermore, the
highly selective carbopalladation of dinitriles with organoboron reagents
to give long-chain ketonitriles has been developed as well. Based
on the broad scope of substrates, excellent functional group tolerance,
and use of commercially available substrates, the Pd-catalyzed addition
reaction of arylboronic acid and dinitriles is expected to be significant
in future synthetic procedures.
The first example of the nickel-catalyzed tandem addition/cyclization of 2-(cyanomethyl)benzonitrilesw ith arylboronic acids in 2-MeTHF has been developed, which provides the facile synthesis of aminoisoquinolines with good functional group tolerance under mild conditions. This chemistry has also been successfully appliedt ot he synthesis of isoquinolones by the tandemr eaction of methyl 2-(cyanomethyl)benzoates with arylboronic acids. The use of the biobased and green solvent2 -MeTHF as the reaction medium makes the synthesis process environmentally benign. The synthetic utility of this chemistry is also indicatedbythe synthesis of biologically activemolecules.Scheme1.Transformation of organonitriles.[a] Q.Supporting information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.
The first example of nickel complexes as effectively catalyst to C–C, N–C cascade coupling of ketonitriles with arylboronic acids, affording 2,5-diarylpyrroles and 2,6-diarylpyridines.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.