Tuning the Selectivity: Study of Solvent‐Free Acid‐Mediated Pinacolic‐Pinacolone Rearrangement under Microwave Irradiation

Abstract

Here we report an efficient solvent‐free pinacolic‐pinacolone rearrangement using supported acids. Given a standard procedure (5 minutes microwave heating at 180 °C), changing the acid catalyst allow to reverse the selectivity of the reaction. The optimized conditions represent an efficient means by which pinacol‐pinacolone rearrangement can be carried out while avoiding the use of strong homogeneous Brönsted acids and extended reaction times. This neat reaction gave the products in high yield, purity and ease of recovery. Moreover, the catalyst can be reused on 10 runs without any loss of activity nor selectivity. As a consequence, that protocol can be referred as a green and efficient process for pinacol‐pinacolone rearrangement.

Advances and Perspectives in Pinacol Rearrangement Reactions: A Comprehensive Review

“…The paper titled "Tuning the Selectivity: Study of Solvent-Free Acid-Mediated Pinacolic-Pinacolone Rearrangement under Microwave Irradiation" published in ChemistrySelect investigates the selectivity of the pinacol-pinacolone rearrangement under solvent-free conditions and microwave irradiation. The study focuses on understanding the influence of reaction parameters, such as acid catalysts and reaction conditions, on the selectivity of this important organic transformation [34]. The authors highlight the significance of the pinacol-pinacolone rearrangement as a versatile reaction for the synthesis of carbonyl compounds.…”

Direct Deoxygenation of α-Hydroxy and α,β-Dihydroxy Ketones Using a Silyl Lithium Reagent

“…1,2-Diphenylethan-1-one (5b). 20 Isolated yield of 128 mg, 93%, purified by silica gel column chromatography (99:1 petroleum ether/ ethyl acetate), white crystalline solid; 1 2-Hydroxy-1,2-di-m-tolylethan-1-one (8a). 19 White crystalline solid; 1 1,2-Di-m-tolylethan-1-one (8b).…”

“…19 White crystalline solid; 1 1,2-Di-m-tolylethan-1-one (8b). 20 Isolated yield of 85 mg, 92%, purified by silica gel column chromatography (99:1 petroleum ether/ ethyl acetate), white crystalline solid; 1…”

“…1,2-Diphenylethan-1-one (5b). 20 Isolated yield of 128 mg, 93%, purified by silica gel column chromatography (99:1 petroleum ether/ ethyl acetate), white crystalline solid; 1 1,2-Di-m-tolylethan-1-one (8b). 20 Isolated yield of 85 mg, 92%, purified by silica gel column chromatography (99:1 petroleum ether/ ethyl acetate), white crystalline solid; 1…”