Chiral Lewis acid catalysis in a visible light-triggered cycloaddition/rearrangement cascade

Chem Sci. 2022 Sep 23;13(40):11856-11862. doi: 10.1039/d2sc03159k. eCollection 2022 Oct 19.

ABSTRACT

Cascade (domino) reactions facilitate the formation of complex molecules from simple starting materials in a single operation. It was found that 1-naphthaldehyde derivatives can be converted to enantioenriched (82-96% ee) polycyclic benzoisochromenes via a cascade of ortho photocycloaddition and ensuing acid-catalysed rearrangement reactions. The cascade was initiated by irradiation with visible light (λ = 457 nm) and catalysed by a chiral AlBr3-activated 1,3,2-oxazaborolidine (14 examples, 65-93% yield). The absolute configuration of the products was elucidated by single crystal X-ray crystallography. Mechanistic experiments suggest that the ortho photocycloaddition occurs on the triplet hypersurface and that the chiral catalyst induces in this step the observed enantioselectivity.

PMID:36320923 | PMC:PMC9580482 | DOI:10.1039/d2sc03159k

Share:

Related Posts

Leave a Reply

Your email address will not be published. Required fields are marked *

Generated by Feedzy