Vinylation of different hydroxyl groups by CaC2/KF solid acetylene reagent
A combination of two simple compounds – calcium carbide (CaC2) and potassium fluoride (KF) – creates a very efficient acetylene reagent with enhanced reactivity. In the presence of water, acetylene is generated in this system and is activated towards an in situ reaction with alcohols and phenols. Efficient vinylation converts the hydroxyl group (–OH) of alcohols and phenols into the H2C=CH-O- building block. The hydroxyl group is a widespread functional group involved in a number of core organic transformations. Post-modification of drugs and biologically active molecules is an emerging area of very demanding applications of the vinylation reaction described. Biomedicine, material science and production of monomers are other well-appreciated areas of application of such vinyl monomers.
Mechanistic studies by experiment and computations have revealed two important factors: 1) the etching of the surface of CaC2 by KF in the solid state; and 2) the fluoride-mediated activation in solution, which governs the enhanced reactivity in the developed system. The CaC2/KF system described in the present study has crucial advantages compared to gaseous acetylene.
Acetylene is a fundamental and one of the most known organic molecules. However, acetylene is a flammable and explosive gas, which is very difficult to handle in laboratory. Using high pressure of acetylene requires complicated and expensive equipment with severe safety regulations. The CaC2/KF system described in the present study has crucial advantages compared to gaseous acetylene. With this efficient CaC2/KF solid acetylene reagent a number of remarkable applications can be anticipated.
The article "A solid acetylene reagent with enhanced reactivity: fluoride-mediated functionalization of alcohols and phenols" was published in the Green Chemistry journal (The Royal Society of Chemistry).
Reference: Werner G., Rodygin K.S., Kostin A.A., Gordeev E.G., Kashin A.S., Ananikov V.P, Green Chem., 2017.
DOI: 10.1039/c7gc00724h
On-line link: http://doi.org/10.1039/c7gc00724h
