Reduction of phenylacetylenes using Raney Ni–Al alloy, Al powder in the presence of noble metal catalysts in water

Abstract

The chemoselective reduction is based on the reaction between Al either as powder or from the alloy and water which generates in situ hydrogen to effect the reduction of the targeted functional groups. Raney Ni-Al alloy with Al powder can reduce phenylacetylenes to the corresponding ethylbenzene (3) in water in excellent yield at 120 °C for 6 h in a sealed tube. In addition, the complete reduction of the aromatic ring to ethylcyclohexane required 60 o C for 12 h with Raney Ni-Al alloy, Al powder in the presence of Pt/C. Appropriate selection of reaction conditions allowed the selective preparation of ethylbenzene as well as ethylcyclohexane from phenylacetylene.

A Review on the Recent Advances in the Reductions of Carbon–Carbon/Oxygen Multiple Bonds Including Aromatic Rings Using Raney Ni–Al Alloy or Al Powder in the Presence of Noble Metal Catalysts in Water

“…radical in high yield. On the other hand, the addition of Pt/C to the mixture of Raney Ni-Al and Al powder was found to be the best catalytic system for the reduction of the aromatic ring at 60 o C for 12 h which generates sufficient nascent hydrogen [141]. Nowadays, much attention has been devoted to the development of methods involving safe, convenient reagents and solvents to minimize waste formation leading to environmentally sustainable process.…”