Nitrogen–nitrogen bonds containing
motifs are ubiquitous
in natural products and bioactive compounds. However, the atropisomerism
arising from a restricted rotation around an N–N bond is largely
overlooked. Here, we describe a method to access the first enantioselective
synthesis of N–N biaryl atropisomers via a Cu-bisoxazoline-catalyzed
Friedel–Crafts alkylation reaction. A wide range of axially
chiral N–N bisazaheterocycle compounds were efficiently prepared
in high yields with excellent enantioselectivities via desymmetrization
and kinetic resolution. Heating experiments showed that the axially
chiral bisazaheterocycle products have high rotational barriers.
N−C Biaryl atropisomers are prevalent in natural products and bioactive drug molecules. However, the enantioselective synthesis of such molecules has not developed significantly. Particularly, the enantioselective synthesis of N−C biaryl atropisomers by stereoselective metal‐catalyzed aryl amination remains unprecedented. Herein, a Pd‐catalyzed cross‐coupling strategy is presented for the synthesis of N−C axially chiral biaryl molecules. A broad spectrum of N−C axially chiral compounds was obtained with excellent enantioselectivities (up to 99 % ee) and good yields (up to 98 %). The practicality of this reaction was validated in the synthesis of useful biological molecules.
Diarylamines and related scaffolds are ubiquitous atropisomeric chemotypes in biologically active natural products. However, the catalytic asymmetric synthesis of these axially chiral compounds remains largely unexplored. Herein, we report that a BINOL‐derived chiral phosphoric acid (CPA) successfully catalyzed the atroposelective coupling of quinone esters and anilines through direct C−N bond formation to afford N‐aryl quinone atropisomers with an unprecedented intramolecular N−H−O hydrogen bond within a six‐membered ring in good yields and enantioselectivities with the quinone ester as both the electrophile and the oxidant. A gram‐scale experiment demonstrated the utility of this synthetic protocol. Moreover, this methodology provides a platform for the synthesis of structurally diverse secondary amine atropisomers by nucleophilic addition.
Vinyl cyclopropanes (VCPs) are among the most useful three-carbon building blocks in organic synthesis. They are commonly used as dienophiles in a range of cycloaddition reactions. However, VCP rearrangement has...
N−C Biaryl atropisomers are prevalent in natural products and bioactive drug molecules. However, the enantioselective synthesis of such molecules has not developed significantly. Particularly, the enantioselective synthesis of N−C biaryl atropisomers by stereoselective metal‐catalyzed aryl amination remains unprecedented. Herein, a Pd‐catalyzed cross‐coupling strategy is presented for the synthesis of N−C axially chiral biaryl molecules. A broad spectrum of N−C axially chiral compounds was obtained with excellent enantioselectivities (up to 99 % ee) and good yields (up to 98 %). The practicality of this reaction was validated in the synthesis of useful biological molecules.
Diarylamines and related scaffolds are ubiquitous atropisomeric chemotypes in biologically active natural products. However, the catalytic asymmetric synthesis of these axially chiral compounds remains largely unexplored. Herein, we report that a BINOL‐derived chiral phosphoric acid (CPA) successfully catalyzed the atroposelective coupling of quinone esters and anilines through direct C−N bond formation to afford N‐aryl quinone atropisomers with an unprecedented intramolecular N−H−O hydrogen bond within a six‐membered ring in good yields and enantioselectivities with the quinone ester as both the electrophile and the oxidant. A gram‐scale experiment demonstrated the utility of this synthetic protocol. Moreover, this methodology provides a platform for the synthesis of structurally diverse secondary amine atropisomers by nucleophilic addition.
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