A Unique Synthesis of 5,8-Difluoro‑2<i>H</i>‑chromene Using Silicone Oil as a Solvent

A significantly improved synthesis of 5,8-difluoro-2<i>H</i>-chromene <b>1</b> using silicone oil as the reaction solvent is described. The new method eliminated the tedious workup and large quantity of waste produced via conventional methods. To our best knowledge, this is the first report of conducting an organic reaction using silicone oil as an organic solvent

Regioselective Functionalization of 4‑Methyl‑1<i>H</i>‑indole for Scalable Synthesis of 2‑Cyano-5-formyl-4-methyl‑1<i>H</i>‑indole

We report a five-step synthesis of 2-cyano-5-formyl-4-methyl-1<i>H</i>-indole through sequential functionalization of readily available 4-methyl-1<i>H</i>-indole. Cyano and aldehyde functionalities are regioselectively installed at the 2 and 5 position, respectively. The sequence is concise and high-yielding, amenable for kilogram scale production