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.