I'm not sure if the H2/Nickle combination will work here. Why're you insisting on it?
In general, just use Hydrogen + Nickle/Platinum catalyst to reduce C=C bonds and use aqueous sodium tetrahydridoborate or anhydrous lithium tetrahydridoaluminate in an ethoxyethane solvent to reduce carbonyl groups.
I'm not sure if the H2/Nickle combination will work here. Why're you insisting on it?
In general, just use Hydrogen + Nickle/Platinum catalyst to reduce C=C bonds and use aqueous sodium tetrahydridoborate or anhydrous lithium tetrahydridoaluminate in an ethoxyethane solvent to reduce carbonyl groups.
in the unit 4 IAL paper last week, there was a question about a molecule containing both C=C and C=O bonds that was reacted with H2/Ni and we had to draw the structure of the product...
in the unit 4 IAL paper last week, there was a question about a molecule containing both C=C and C=O bonds that was reacted with H2/Ni and we had to draw the structure of the product...
I see. From what I've seen, a variety of answers are acceptable for things which can reduce the C=O bond, such as hot zinc and ethanol, but Ni/Hydrogen has never been mentioned. I personally think it can't reduce the C=O but I can't find conclusive evidence. Whatever, the exam's over. Don't stress.
Since reduction is defined as addition of hydrogen, dihydrogen (H2) would seem to be the ideal reducing agent. However, the strength of the H-H bond and the lack of polarizability of the molecule makes it extremely unreactive. Fortunately some precious metals - platinum, palladium, nickel - "react" with dihydrogen in a rather unusual way. The metals dissolve dihydrogen and partially bond to it, effectively breaking the H-H bond; platinum will dissolve more than a mole of hydrogen and swells visibly in the process - it is like a sponge. Thus these metals serve as catalysts for reactions of dihydrogen. Typically dihydrogen adds to multiple bonds - alkenes, alkynes, carbonyl compounds - in the presence of these catalysts. Since the hydrogenation reaction takes place on the surface, it is stereospecific syn.
By careful control of the reaction conditions and the exact nature of the catalyst, it is possible to reduce one kind of multiple bond without some others that are present reacting. An alkyne can be reduced to a Z (cis) alkene by "poisoning" the Pt catalyst so that the addition stops at the alkene; reagents that have been used are sulfur compounds such as barium sulfate, organic amines such as quinoline. A weakened palladium catalyst called Lindlar's catalyst (Pd with CaCO3 and Pb(OAc)2 is very popular too. With a weaker catalyst or much milder conditions, it is possible to reduce an alkene without reducing a carbonyl in the same molecule, even if they are conjugated."