Addition of Grignard Reagents to Nitroarenes

A short critical review of current literature has appeared (Ricci A et al, Ang Chem Int Edn, 2003, 42, 1444), prompted by recent work from the group of Knochel (J Am Chem Soc, 2002, 124, 9390) on diarylamine synthesis.

This work nicely complements the Buchwald-Hartwig methodology for diarylamine synthesis.  Previously, Bartoli had used the reaction of vinyl Grignard reagents with nitroarenes as a novel method to produce indoles.  This is a complex process involving 6 intermediate steps (see for example Bartoli G et al, J Chem Soc Perkin Trans I, 1991, 2757) but can be a useful synthetic scheme if an ortho substituent is present.

The methodology has recently been extended to produce highly functionlised indoles (Dobbs A, J Org Chem, 2001, 66, 638).