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

Abstract

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.

Extended Corey–Chaykovsky reactions: transformation of 2-hydroxychalcones to benzannulated 2,8-dioxabicyclo[3.2.1]octanes and 2,3-dihydrobenzofurans

“…of trimethylsulfoxonium iodide and 3 equiv. of NaH in DMSO afforded donor-acceptor cyclopropane 4a in a good yield 17 (Table 1, entry 1). Further increase of NaH loading however led to a decrease in the yield of 4a, and instead, ketal 2a was obtained as the main product (Table 1, entry 2).…”

“…16 Aiming to develop the extended Corey-Chaykovsky reaction as a general approach in organic chemistry, we decided to demonstrate its efficiency in the preparation of some heterocyclic compounds from simple electrophilic alkenes. To start this project, we selected 2-hydroxychalcones as substrates accounting for both the possibility of their transformation to the corresponding aryl 2-(2-hydroxyphenyl)cyclopropyl ketones 17 and the high reactivity of donor-acceptor cyclopropanes bearing the 2-hydroxyaryl group as a donor substituent in diverse processes. 18 Herein, we report the extended Corey-Chaykovsky reactions of 2-hydroxychalcones 1 yielding 2,8-dioxabicyclo[3.2.1]octanes 2 and 2,3-dihydrobenzofurans 3.…”

Protic Ionic Liquid as Reagent, Catalyst, and Solvent: 1‐Methylimidazolium Thiocyanate

“…To achieve further proof of concept for the triple role of PILs, we employed 1‐methylimidazolium thiocyanate to perform the annulation of isothiocyanic acid with 2‐hydroxyphenyl‐derived cyclopropane 1 ah , [32] serving as the equivalent of the corresponding ortho ‐quinone methide [33] . Indeed, under heating in HMimNCS at 70 °C, cyclopropane 1 ah was smoothly transformed into [1,3]benzoxazine‐2‐thione 7 in reasonable yield.…”