Hexafluoroisopropanol Promoted Ring‐Opening‐Cyclization of Donor–Acceptor Cyclopropanes with Primary Amines

Abstract

We reveal here a metal‐free, ring‐opening‐cyclization of donor‐acceptor cyclopropanes with primary amines to synthesize functionalized dihydropyrroles. This protocol avoids inert conditions and solvents promoted by hexafluoroisopropanol (HFIP). The reaction is quite general with aryl, alkyl, and alicyclic amines. A good number of cyclopropanes bearing keto groups reacted excellently to produce the desired products. Further, we complemented this method with Meldrum's acid‐derived cyclopropanes for synthesizing g‐lactams. We have demonstrated the post‐synthetic applications of the products and gram‐scale synthesis to highlight the adaptability of this synthetic protocol.

Mechanochemical Cascade Cyclization of Cyclopropyl Ketones with 1,2-Diamino Arenes for the Direct Synthesis of 1,2-Disubstituted Benzimidazoles

“…Furthermore, mechanochemistry has gained growing popularity over classical solution-based methods due to its potential to enable reactions faster, promote solvent-free conditions, and improve sustainability metrics. , To the best of our knowledge, the chemistry of DAC in ball mills has remained unexplored. In continuation of our research interest toward harnessing the ambiphilic reactivity of DAC, recently, we developed a metal-free approach for the synthesis of 2,3-dihydropyrroles using 1,1,1,3,3,3-hexafluoroisopropanol (HFIP). , In this connection, we wanted to develop a metal-free approach for the 1,2-disubstituted benzimidazoles through domino ring-opening cyclization using mechanochemical conditions (Scheme ).…”