Mechanically Planar-to-Point Chirality Transmission in [2]Rotaxanes

© 2024. The authors. This document is made available under the CC-BY 4.0 license http://creativecommons.org/licenses/by /4.0/ This document is the published version of a published work that appeared in final form in Journal of the American Chemical Society (JACS). To access the final work, see DOI: https://doi.org/10.1021/jacs.3c11611Herein we describe an effective transmission of chirality, from mechanically planar chirality to point chirality, in hydrogen-bonded [2]rotaxanes. A highly selective mono-N-methylation of one (out of four) amide N atom at the macrocyclic counterpart of starting achiral rotaxanes generates mechanically planar chirality. Followed by chiral resolution, both enantiomers were subjected to a base-promoted intramolecular cyclization, where their interlocked threads were transformed into new lactam moieties. As a matter of fact, the mechanically planar chiral information was effectively transferred to the resulting stereocenters (covalent chirality) of the newly formed heterocycles. Upon removing the entwined macrocycle, the final lactams were obtained with high enantiopurity

Synthesis and Characterization of Axially Chiral Imidazoisoquinolin-2-ylidene Silver and Gold Complexes

The selective Suzuki cross-coupling of 1,3-dichloroisoquinoline with 2-substituted 1-naphthylboronic acids/esters followed by construction of the imidazo­[1,5-<i>b</i>]­isoquinoline ring and alkylation constitutes a straightforward route to imidazolium salts fused into an axially chiral biaryl skeleton. Metalation of these azolium salts afforded the corresponding NHC silver complexes, which were used as carbene transfer agents for the synthesis of Au­(I) derivatives

Mechanically Planar-to-Point Chirality Transmission in [2]Rotaxanes

Herein we describe an effective transmission of chirality, from mechanically planar chirality to point chirality, in hydrogen-bonded [2]rotaxanes. A highly selective mono-N-methylation of one (out of four) amide N atom at the macrocyclic counterpart of starting achiral rotaxanes generates mechanically planar chirality. Followed by chiral resolution, both enantiomers were subjected to a base-promoted intramolecular cyclization, where their interlocked threads were transformed into new lactam moieties. As a matter of fact, the mechanically planar chiral information was effectively transferred to the resulting stereocenters (covalent chirality) of the newly formed heterocycles. Upon removing the entwined macrocycle, the final lactams were obtained with high enantiopurity

Synthesis and Characterization of Axially Chiral Imidazoisoquinolin-2-ylidene Silver and Gold Complexes

The selective Suzuki cross-coupling of 1,3-dichloroisoquinoline with 2-substituted 1-naphthylboronic acids/esters followed by construction of the imidazo­[1,5-<i>b</i>]­isoquinoline ring and alkylation constitutes a straightforward route to imidazolium salts fused into an axially chiral biaryl skeleton. Metalation of these azolium salts afforded the corresponding NHC silver complexes, which were used as carbene transfer agents for the synthesis of Au­(I) derivatives

Axially Chiral Triazoloisoquinolin-3-ylidene Ligands in Gold(I)-Catalyzed Asymmetric Intermolecular (4 + 2) Cycloadditions of Allenamides and Dienes

The first highly enantioselective intermolecular (4 + 2) cycloaddition between allenes and dienes is reported. The reaction provides good yields of optically active cyclohexenes featuring diverse substitution patterns and up to three stereocenters. Key to the success of the process is the use of newly designed axially chiral <i>N</i>-heterocyclic carbene–gold catalysts