Synthesis of Fluoro Isoquinolines via Quinodimethide (QM) Intermediates

Significance

A base-promoted conversion of N-(o-trifluoromethyl)-benzyl heterocycles 1 into fluorinated isoquinolines in moderate to good yields is presented. The reaction is likely to proceed via quinodimethide (QM) intermediates, formed by elimination of HF. Following cycloaddition, the zwitterionic intermediate undergoes re­aromatization by elimination of a second equivalent of HF. The starting materials 1 are easily and efficiently obtained by reaction of a variety of hetero­cycles with commercially available o-trifluoromethylbenzyl chloride.