copper mediated coupling

[Organikum]

I read an old RatHead post where he talks on the possibility to react BzCl with copper-acetylide in dry ether to yield phenylacetone.
For I am interested in coppermediated coupling-reactions at all I ask if somebody could provide me with a ref or nearer information on this reaction and its mechanism.

Yes I know what copper-acetylide is and I dont plan to try this - possibly highly explosive reaction. A fulminant compound in ether is even for my taste - too hot.

thanks
ORG

[Rhodium]

Link to the post in question, that makes it easier for us to follow. Without having read his particular post, it looks like his idea is very similar to

Post 379214

(fallen_Angel: "P2P - new idea.", Novel Discourse)

[Organikum]

Post 93206 (missing)

(RatHead: "Benzene", Chemicals & Equipment)
There is not much more information in the post as you will see Rhodium. I only left away the preparation of copper-acetylide for reasons of preventing possible accidents as this compound is really fulminant but so simple prepared by venting acetylene into a ammoniawater/cuprous chloride solution, CuSO4 should work also, the details are in VOGELs 3rd - for the interested. (the prep was from memory, so please look it up, or even better, let it go)

The similarity to fallen angels idea isnt obvious to me, sorry.

RatHeads suggestions worked well.

[Rhodium]

When comparing RatHead's idea with that of fallen_angel, I thought you were interested in the general reaction sequence:

Acetylene -> Metal Acetylide -> Phenylpropyne -> P2P

...and not organocopper couplings in general. To better provide you with what you probably are looking for, I scanned the first chapter of one of my books for you (ISBN 0-89874-853-4), hopefully it will answer your questions, and if not - check out the bibliography section on page 8 and 9.

An Introduction to Synthesis Using Organocopper Reagents
Gary H. Posner

Chapter 1 - Introduction

(https://www.thevespiary.org/rhodium/Rhodium/pdf/organocopper.pdf)

[Organikum]

I will read it.

[Nicodem]

I also wish to thank you Rhodium for scaning part of the book - I couldn't get it in my country.

Maybe there is a way to avoid using Cu2C2.
By using just catalytic amounts of CuCl in an ether/pyridine + benzylchloride solution saturated with acetilene. The only reason of failure that I can think of would be that the resulting Ph-CH2-C2H reacts more readilly with CuCl than C2H2 does. But since the copper-carbon bond is almost covalent the same logic as with sodium and the pKa rules don't apply. But I'm sure there are plenty of other posibilities of failure as there always are. Any other idea?

Anyway Cu2C2is only dangerous when dried, but I would also prefer to avoid it, especially if in larger quantities.

[Organikum]

or is copper-acetylide also stable in dry ether? I strongly guess this to be so or the reaction as proposed by RatHead would be near to impossible to do at all....

So the water would have to be distilled away by azeotropic distillation with ether or another usable solvent - benzene/ethylalcohol/water as ternary azeotrope might work - keeping the acetylide always well covered.....
Just spinning on the theoretical string...

I prepared copper-acetylide once and it is realy as impressing as told in Vogel´s 3rd - beats nitrogentriiodide by far....

[Nicodem]

I only know that it wont't explode until it is dry of water, but if it is similar to other explosives it will be stable in other solvents also. However I would never ever think of puting it in a boiling solution of ether even if just somewhere more than 30°C. Call me a coward, but my memory of Cu2C2 is that it makes a really big bum! But it is not at all as much so shock sensitive as NI3. And remember Cu2C2 is an exception as an organometalic since it is stable in protic solvents. There may be no need to use ether, DMF would probably disolve it (thoug it is more expensive).

Therefore I propose to use it only as a catalist. Not just for safety reasons, also for simplicity sake. And this could also help preventing dialkylation.