Phase-Vanishing Method with Acetylene Evolution and Its Utilization in Several Organic Syntheses

Abstract

A novel quadraphasic phase-vanishing system in which acetylene is evolved from calcium carbide and directly applied in situ to the Sonogashira coupling reaction was developed. This method, which provides a safe, convenient, and one-pot means to utilize gaseous reagents without special equipment, was also applied to a Cu-catalyzed azide-alkyne cycloaddition (CuAAC) reaction and a three-component aldehyde-alkyne-amine (A(3)) coupling reaction with excellent results.

Calcium Carbide: A Unique Reagent for Organic Synthesis and Nanotechnology

“…One important factor that needs to be tuned for the optimal generation of acetylene is the reaction between CaC 2 and water. To tackle this issue, a useful multiphase procedure was proposed for conducting the reactions . In this one‐pot system, the bottom layer, which contained calcium carbide, was separated from the water phase by a fluorous solvent (Galden HT135), which acted like a liquid membrane and facilitated water and heat transport in a controllable manner (Figure ).…”

Phase-vanishing method with gas evolution and its application to organic synthesis

“…5 This method also utilized the passive diffusion of water into the fluorous solvent to obtain gradual evolution of acetylene gas from calcium carbide. Therefore, this method is advantageous for reactions requiring acetylene gas as it avoids the use of high-pressure apparatus, such as regulators and gas cylinders.…”

“…5 For this purpose, CaH 2 (8 mmol, ρ = 1.70 g cm −3 ) was used as the source of hydrogen in the reagent phase (bottom layer), and THF (ρ = 0.89 g cm −3 ) was used as the organic phase (top layer). Galden HT135 (ρ = 1.72 g cm −3 ) was employed as the fluorous phase, and water (22 mmol) was placed above it.…”

“…1 Meanwhile, we developed a novel synthetic methodology using fluorous solvents as a phase screen, known as the 'phase-vanishing (PV) method'. [2][3][4][5] The PV method involves a triphasic reaction system, in which fluorous media are used as a liquid membrane to steadily transport reagents from the lower layer to the upper organic layer that includes the substrate. In the PV method, the fluorous phase regulates the transport of reagents by passive diffusion.…”

Calcium‐Based Sustainable Chemical Technologies for Total Carbon Recycling

“…Calcium hydroxide released after the reaction of CaC 2 with water may even serve as an additional in situ formed base . Phase separation in a single reaction vessel may be achieved by using a carefully selected mixture of solvents (Figure B) . A more general setup includes standard two‐vessel reactors (H‐tube, etc.)…”