A simple one-pot oxidation protocol for the synthesis of dehydrohedione from Hedione

A new method for the oxidation of Hedione 1 to dehydrohedione 2, a high value intermediate in the flavour and fragrance industry, has developed based upon one pot α-chlorination-elimination sequence which can be readily scaled. The spontaneous elimination of the α-chloro in methanol was unprecedented and has allowed for the oxidation, typically performed in multiple steps/reactions, to be carried out as a one-pot protocol. A continuous flow process for performing the reaction utilising sulfuryl chloride has also demonstrated allowing for steady, safe evolution of SO2 gas during the reaction

Further investigations into imine-mediated formation of allylic nitro compounds

Nitro alkanes are valuable starting materials for functionalisation via their corresponding anions as well as their transformation into other important groups such as ketones via the Nef reaction. Herein, we report a process development study for the construction of a series of cyclic allylic nitro compounds that features a greener solvent and a lower cost, more robust catalyst than previously reported. The process was developed to target the selective synthesis of an important fragrance intermediate, namely, α-dehydroherbac. Process scoping and optimisation involved solvent & catalyst screening along with a basic kinetic investigation to evaluate critical reaction parameters (concentration and reagents ratio). The final optimised conditions were further demonstrated via synthesis of a small collection of additional derivatives to demonstrate scope and utility

Spectroscopic dataset of Hedione's derivatives gathered during process development

The dataset of spectroscopic analysis performed on starting materials, intermediates, and products relating to the synthesis of Hedione are hereby presented. The data were acquired in Durham university during the period between October 2020 and September 2021 for the development of a preparative method to Dehydrohedione. The latter is a key intermediate for the synthesis of cis-Hedione, an important fragrance ingredient. Proton, Carbon-13, and Fluorine-19 Nuclear magnetic resonance of the compounds were recorded employing a Varian 600 MHz, and a Bruker Avance-400 instrument. The IR spectra were recorded in a Perkin Elmer Spectrum Two UATR Two FT-IR and the accurate mass employing a Waters QtoF premier as mass spectrometer