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Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
The Role of N-Substitution in Regio- and Stereoselective Vinylogous Imidonaphthoquinone (VINAquinone) [2 + 2]
Ian Merski1, Jinya Yin1, Ryan T VanderLinden1
1Department of Chemistry, University of Utah, 315 South 1400 East, Salt Lake City, Utah 84108, United States.
Abstract:
Described in this manuscript are intramolecular [2 + 2] photocycloadditions of readily available vinylogous imidonaphthoquinones whose regio- and diastereoselectivity is dependent on the substitution on the vinylogous imide. When exposed to 419 nm light, 2° vinylogous imidonaphthoquinones give novel bridged tetracyclic aza-anthraquinones from a rare crossed [2 + 2] cycloaddition reaction. In contrast, exposure of the corresponding 3° substrates to white light leads to linear adducts. Also outlined here are auxiliary controlled diastereoselective reactions and cyclobutane fragmentations as a means of generating the spirofused γ-lactam moiety present in the ansalactam family of natural product.
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