Synthesis of (Het)aryl 2-(2-hydroxyaryl)cyclopropyl Ketones

A simple general method for the synthesis of 1-acyl-2-(ortho-hydroxyaryl)cyclopropanes, which belong to the donor–acceptor cyclopropane family, has been developed. This method, based on the Corey–Chaykovsky cyclopropanation of 2-hydroxychalcones, allows for the preparation of a large diversity of hydroxy-substituted cyclopropanes, which can serve as promising building blocks for the synthesis of various bioactive compounds.

Visible-light-induced triple catalysis for a ring-opening cyanation of cyclopropyl ketones

A ring-opening cyanation of cyclopropyl ketones was developed via a synergistic triple catalysis strategy, providing a wide range of γ-cyanoketones in good reaction efficiencies under mild and eco-friendly conditions.

Lewis acid catalysed asymmetric cascade reaction of cyclopropyl ketones: concise synthesis of pyrrolobenzothiazoles

A concise method to synthesize pyrrolobenzothiazoles via a cascade reaction of cyclopropyl ketones was developed by using a chiral N,N′-dioxide-scandium(iii) complex catalyst.

Lewis Base Catalysis Based on Homoconjugate Addition: Rearrangement of Electron-Deficient Cyclopropanes and Their Derivatives

Cyclopropane is one of the most reactive functionalities owing to its intrinsic ring strain. Transition-metal catalysis and Lewis acid catalysis have been extensively used in ring openings of cyclopropanes; however, Lewis base-catalyzed activation of cyclopropanes remains largely unexplored. Upon nucleophilic attack with Lewis bases, cyclopropanes undergo ring cleavage in a manner known as homoconjugate addition to form zwitterionic intermediates, which have significant potential for reaction development but have garnered little attention. Here, we present a brief overview of this area, with an emphasis on our recent efforts on Lewis base-catalyzed rearrangement reactions of electron-deficient cyclopropanes using the homoconjugate addition process.1 Introduction2 DABCO-Catalyzed Cloke–Wilson Rearrangement of Cyclopropyl Ketones3 Hydroxylamine-Mediated Tandem Cloke–Wilson/Boulton–­Katritzky Reaction of Cyclopropyl Ketones4 Phosphine-Catalyzed Rearrangement of Vinylcyclopropyl Ketones To Form Cycloheptenones5 Phosphine-Catalyzed Rearrangement of Alkylidenecyclopropyl Ketones To Form Polysubstituted Furans and Dienones6 Conclusion and Outlook