Transition‐Metal‐Free Synthesis of 1‐Indanone Skeleton: A Brief Update

Abstract

Transition‐metal‐free carbon‐carbon bond forming reactions have drawn great interest because they are operationally simple, cost‐effective and environmentally benign. However, the construction of indanone core under metal‐free condition has been long‐standing challenges to organic chemists. In this article, recent advances (2015–2021) in transition‐metal‐free strategies towards 1‐indanone skeletons are reviewed and they are classified as acid‐catalyzed, base‐catalyzed, organocatalytic and catalyst‐free methods. In most cases, mechanisms for the transformations and stereochemical aspects of the product formation have been demonstrated.

Exploiting the reactivities ofortho-alkynyl aryl ketones: opportunities in designing catalytic annulation reactions

“…26 Moreover, some 1-indanones could behave as key intermediates with great synthetic applications in the total synthesis of natural products and pharmaceuticals. 27 This explains many state-of-the-art methods developed recently for the construction of this bicarbocyclic skeleton, 28 especially radical-induced 5-exo-dig carbocyclization. 29 In this scenario, Tu and Jiang's group designed and synthesized a class of versatile building blocks of ortho-alkynyl aryl ketones incorporating a 1,6-enyne unit and employed them to react with aryldiazonium salts and DABSO (Scheme 9).…”

“…26 Moreover, some 1-indanones could behave as key intermediates with great synthetic applications in the total synthesis of natural products and pharmaceuticals. 27 This explains many state-of-the-art methods developed recently for the construction of this bicarbocyclic skeleton, 28 especially radical-induced 5- exo-dig carbocyclization. 29…”

Brønsted‐Acid‐Catalyzed One‐Pot Synthesis of β,β‐Diaryl Esters: Direct Regioselective Approach to Diverse Arrays of 3‐Aryl‐1‐indanone Cores

“…3‐aryl‐1‐indanone synthesis recently underwent notable advancement owing to the development of organocatalysis viz . Lewis or Brønsted‐acid catalyzed metal‐free strategies [7] . In 2014, Satyanarayana [8] successfully reported a novel, superacid promoted one‐pot process for the synthesis of indanones using high equivalent (5 equiv.)…”

“…Lewis or Brønsted-acid catalyzed metal-free strategies. [7] In 2014, Satyanarayana [8] successfully reported a novel, superacid promoted one-pot process for the synthesis of indanones using high equivalent (5 equiv. ) of TfOH and chalcones as side-products.…”

Annulations involving 1-indanones to access fused- and spiro frameworks

“…[23][24][25][26][27] Due to their ample appliances in different elds, various metal-catalyzed or metal-free methodologies have been adopted to develop 1-indanone core. 28,29 Previously, Chanda and Singh published a review article on synthesis and application of 3-hydroxyindanone scaffolds covering the literature until 2015. 30 However, the last few years have witnessed the emergence of efficient protocols for the target-oriented synthesis of novel annulation products involving 1-indanone moieties.…”