Organocatalytic atroposelective construction of axially chiral nonsymmetric biaryltriols and their applications in asymmetric synthesis and heavy metal ion detection

Abstract

An organocatalytic methodology toward the atroposelective construction of axially chiral nonsymmetric biaryltriols has been successfully developed. A quinine-derived thiourea-catalyzed intramolecular reaction using VQM (vinylidene ortho-quinone methides) intermediates enabled efficient access to a class of axially chiral nonsymmetric biaryltriols with up to 98% yield and 99% ee. This strategy allows the convenient construction of atropoisomeric compounds with broad functional group tolerance under mild conditions. The new biaryltriols can be applied as chiral ligands for the enantioselective preparation of chiral sec-alcohols, or as organocatalysts for the asymmetric Petasis reaction to give the corresponding adducts with up to 95% yield and 83% ee under unmodified reaction conditions. In addition, axially chiral nonsymmetric biaryltriols have demonstrated potential utility as selective fluorescent sensors toward Ru³⁺ ions.