TY - JOUR

T1 - A solid acetylene reagent with enhanced reactivity

T2 - Fluoride-mediated functionalization of alcohols and phenols

AU - Werner, Georg

AU - Rodygin, Konstantin S.

AU - Kostin, Anton A.

AU - Gordeev, Evgeniy G.

AU - Kashin, Alexey S.

AU - Ananikov, Valentine P.

N1 - Funding Information: Synthetic studies were supported by the Russian Science Foundation (grant 16-13-10301). GW acknowledges Saint Petersburg State University for a postdoctoral fellowship (No 0.50.1186.2014). The authors also express their gratitude to the Centre for Magnetic Resonance, X-ray Diffraction Center, the Centre for Chemical Analysis and Materials Research and the Interdisciplinary Center for Nanotechnology (Saint Petersburg State University). Mechanistic studies using theoretical calculations and microscopy were supported by Russian Science Foundation (RSF grant 14-50-00126). The authors thank Dr Yan Zubavichus and Victor Khrustalev for carrying out XPD analysis. Publisher Copyright: © 2017 The Royal Society of Chemistry. Copyright: Copyright 2020 Elsevier B.V., All rights reserved.

PY - 2017

Y1 - 2017

N2 - The direct vinylation of an OH group in alcohols and phenols was carried out utilizing a novel CaC2/KF solid acetylene reagent in a simple K2CO3/KOH/DMSO system. The functionalization of a series of hydroxyl-group-containing substrates and the post-modification of biologically active molecules were successfully performed using standard laboratory equipment, providing straightforward access to the corresponding vinyl ethers. The overall process developed involves an atom-economical addition reaction employing only inorganic reagents, which significantly simplifies the reaction set-up and the isolation of products. A mechanistic study revealed a dual role of the F- additive, which both mediates the surface etching/renewal of the calcium carbide particles and activates the CC bond towards the addition reaction. The development of the fluoride-mediated nucleophilic addition of alcohols eliminates the need for strong bases and may substantially extend the areas of application of this attractive synthetic methodology due to increasing functional group tolerance. As a replacement for dangerous and difficult to handle high-pressure acetylene, we propose the solid reagent CaC2/KF, which is easy to handle, does not require dedicated laboratory equipment and demonstrates enhanced reactivity of the acetylenic triple bond. Theoretical calculations have shown that fluoride-mediated activation of the hydroxyl group towards nucleophilic addition significantly reduces the activation barrier and facilitates the reaction.

AB - The direct vinylation of an OH group in alcohols and phenols was carried out utilizing a novel CaC2/KF solid acetylene reagent in a simple K2CO3/KOH/DMSO system. The functionalization of a series of hydroxyl-group-containing substrates and the post-modification of biologically active molecules were successfully performed using standard laboratory equipment, providing straightforward access to the corresponding vinyl ethers. The overall process developed involves an atom-economical addition reaction employing only inorganic reagents, which significantly simplifies the reaction set-up and the isolation of products. A mechanistic study revealed a dual role of the F- additive, which both mediates the surface etching/renewal of the calcium carbide particles and activates the CC bond towards the addition reaction. The development of the fluoride-mediated nucleophilic addition of alcohols eliminates the need for strong bases and may substantially extend the areas of application of this attractive synthetic methodology due to increasing functional group tolerance. As a replacement for dangerous and difficult to handle high-pressure acetylene, we propose the solid reagent CaC2/KF, which is easy to handle, does not require dedicated laboratory equipment and demonstrates enhanced reactivity of the acetylenic triple bond. Theoretical calculations have shown that fluoride-mediated activation of the hydroxyl group towards nucleophilic addition significantly reduces the activation barrier and facilitates the reaction.

UR - http://www.scopus.com/inward/record.url?scp=85024472745&partnerID=8YFLogxK

U2 - 10.1039/C7GC00724H

DO - 10.1039/C7GC00724H

M3 - Article

AN - SCOPUS:85024472745

VL - 19

SP - 3032

EP - 3041

JO - Green Chemistry

JF - Green Chemistry

SN - 1463-9262

IS - 13

ER -