Rhodium(III)-Catalyzed Redox-Neutral Synthesis of Isoquinolinium Salts via C–H Activation of Imines

Redox-neutral
synthesis of isoquinolinium salts via C–H
activation of presynthesized or in situ formed imines and coupling
with α-diazo ketoesters has been realized, where a zinc salt
promotes cyclization as well as provides a counteranion. Under three-component
conditions, both ketone and aldehydes are viable arene sources. The
coupling of imines with diazo malonates under similar conditions afforded
isoquinolin-3-ones as the coupling product.