Organometallic Reagents: Efficient Tools for the Synthesis of Fused Pyridinyl‐Lactones

Abstract

AbstractHerein we disclose an efficient one‐pot route to a wide range of 3‐substituted fused pyridinyl‐lactones, so called aza‐phthalides. The developed strategy involves a Metal/Halogen Exchange (MHE) reaction as key step, followed by an electrophile trapping using various carbonyl derivatives and a subsequent lactonization. To promote the MHE reaction with high chemoselectivity, our investigations have particularly focused on the nature of mono‐ or bimetallic derivatives as metalation reagents including organolithiums, Grignard reagents and lithium organomagnesiate complexes, and highlighted the positive salt effect on reactional sequence. An extension to fused heteroaryl‐lactones (benzothienyl‐, benzofuranyl‐ and naphthofuranyl scaffolds) was explored.