Exploring the Labile Nature of 2, 4, 6‐Trimethoxyphenyl Moiety in Allylic Systems under Acidic Conditions. Issue 30 (27th July 2020)

• Record Type: Journal Article
• Authors: Paul, Dipankar; Chatterjee, Paresh Nath
• Is Part Of: European journal of organic chemistry. Issue 30(2020)
• Page Start: 4705
• Page End: 4712
• Publication Date: 2020-07-27
• Subjects: C–C bond activation -- Allylation of arene -- 1, 3, 5‐Trimethoxybenzne -- Carbon‐based leaving group -- Acidic labilization of aryl group; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.202000631
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract : An investigation of the unexpected lability of the Csp³ –Csp² bond connecting 2, 4, 6‐trimethoxyphenyl group and an allylic moiety is carried out. We observed that the catalytic presence of either Lewis or Brønsted acid can render such 2, 4, 6‐trimethoxyphenyl group labile. Several nucleophiles were found to substitute the labile C–C bond in mild reaction conditions resulting in very good yields of the allylated products. Even in the absence of a nucleophile, intramolecular cyclization of the parent substrate under acidic activation caused the labile C–C bond to cleave. A major motivation of this study is to understand the lability of electron‐rich aryl group in acidic medium, employing 2, 4, 6‐trimethoxyphenyl moiety as a case study. A plausible mechanism is proposed after carrying out several control reactions as well as UV/Vis and 1 H NMR spectroscopic studies. This work provides an insight into the activation of electron‐rich arenes as a labile entity in acidic medium while also adding a conceptually novel C–C bond breaking approach to the vast literature of allylation of arenes. Abstract : A study aimed to comprehend the labile behavior of electron‐rich aryl groups connected to allylic framework under acidic medium is carried out. Reveresible protonation and deprotonation at the ipso ‐carbon was found to be a driving factor in the C–C bond breaking reaction