Visible-Light-Promoted Formylation/Annulation of Isocyanides with Glyoxylic Acid Acetals for the Synthesis of Masked 2-Formyl Phenanthridines and Quinolines.

Herein, we report a visible-light-promoted cascade formylation/annulation of isocyanides with glyoxylic acid acetals, which serves as the aldehyde source, to afford a diverse range of functionalized masked 2-formyl phenanthridines and quinolines. The protocol can be successfully scaled up to a 1 mmol synthesis, and the resulting products can be readily derivatized into corresponding aldehydes, alcohols, and esters in good yields.