Copper(I)-Catalyzed Stereoselective Synthesis of 4‑(Aminomethylene)-1,4-dihydroisoquinolin-3-ones from 4‑Diazo-1,4-dihydroisoquinolin-3-ones and Thioamides

A novel and efficient
approach to synthesize 4-(aminomethylene)-1,4-dihydroisoquinolin-3-ones
has been developed via a copper(I)-catalyzed coupling reaction between
4-diazo-1,4-dihydroisoquinolin-3-ones and thioamides. This method
yields products in good to excellent quantities with remarkable stereoselectivity.
Notably, primary and secondary thioamides consistently produce the
desired compounds with the (Z)-configuration, whereas
tertiary thioamides lead to the formation of products with the (E)-configuration. The versatility and selectivity of this
protocol highlight its potential utility in organic synthesis.