Mild Synthesis of Polyfunctional Benzimidazoles and Indoles by the Reduction of Functionalized Nitroarenes with Phenylmagnesium Chloride

Abstract

Phenylmagnesium chloride has been used for the conversion of selected nitroarenes into nitrenes. Their insertion into a neighboring sp(2) C-H bond yielded functionalized heterocycles. A novel and mild synthesis of polyfunctional benzimidazoles and indoles is described.

Highly Functionalized Organomagnesium Reagents Prepared through Halogen–Metal Exchange

“…An intramolecular C-H insertion is triggered to give the polyfunctionalized indole 130 in 75 % yield. [66] Finally, the reaction of heterocyclic benzothiazoles 131 with functionalized aryl magnesium species 132 provides the functionalized heterocycle 133 in 64 % yield (Scheme 24). [59] …”

Attempts of the Synthesis of Highly Functionalized Porphyrins at the β-Positions: Nitration of Exhaustively Substituted Moieties in the ’Eastern Half ’ and Mass-Spectral Study of the Reaction Products

“…Grignard compounds). [13,14] Leaving aside the detailed discussion on the mechanism, one can accept such organometallic assistance in the transformations described herein because porphyrinates are organometallic compounds. Partially they undergo 'degradation' under the reaction conditions, thus allowing (with small yield; ca.…”

“…The reaction is similar to the fused heterocycles formation pathway (especially indole derivatives). [11,12,14,17] These products are extremely unstable, however, the attempts to confirm their structures by other methods were undertaken. Further manipulation on the moieties to remove paramagnetic Cu 2+ cation and to record NMR spectra for free-base porphyrinoids failed.…”

Synthesis of amines by the electrophilic amination of organomagnesium, -zinc, -copper, and -lithium reagents

“…84 The amount of arylmagnesium reagent can be decreased from 2.3 equivalents to 1.2 equivalents by the use of nitroso arenes as starting materials (Scheme 20). …”