Questions tagged [organotransition-metal-chemistry]

For questions about the use of transition metals in organic synthesis.

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Why is the silver salt ammoniated to form the Tollen's reagent? [duplicate]

When doing a distinguishing test between aldehydes and ketones using Tollen's reagent, is it necessary to convert $\ce{Ag+}$ ions into $\ce{Ag(NH3)2+}$ in order to oxidize the aldehyde?
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43 views

Why is the Suzuki coupling done under inert atmosphere?

There are plenty of sources saying that the Suzuki coupling is air-sensitive (even though there are some versions that require oxygen). However I'd like to know why a typical Suzuki coupling is air-...
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2answers
46 views

Chemoselectively dihydroxylate a terminal alkene in the presence of an internal alkene?

The goal is to dihydroxylate the exo alkene, and then convert to a ketone. Any suggestions would be apprecitated to either chemoselectively convert the terminal alkene, or directly convert the ...
6
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1answer
272 views

Enantioselectivity of Noyori Asymmetric Hydrogenation

I'm unable to understand the enantioselectivity of Noyori's hydrogenation reaction, and would appreciate any help with the same: Here's a mechanism I found on Wikipedia: but, to my disappointment, ...
10
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2answers
5k views

Why is Ni[(PPh₃)₂Cl₂] tetrahedral?

Since PPh₃ is strong field ligand and, the famous Wilkinson's catalyst, which also possess this ligand is square planar, then what makes the above complex tetrahedral?
1
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1answer
358 views

How does the bite angle of a ligand affect the efficiency of its catalyst?

I know that optimising the bite angle of a diphosphine ligand to its metal increases catalytic efficiency, and for cross-coupling reactions larger bite angles are favoured, but how does this have an ...
6
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1answer
149 views

How do the electronic properties of a catalyst affect the rate of oxidative addition?

In my project I have a coupling that was planned to be done using Pd (Suzuki or Stille possibly). Initially, I used an aryl chloride (the SM had already the chloride so I went with it), but the ...
11
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2answers
3k views

What are the byproducts in a Suzuki reaction?

I am looking precisely at a coupling of a trifluoroborate with an aryl bromide. I know the mechanism of the Suzuki reaction, yet I cannot find any mention of the side products or degradation products ...
13
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1answer
218 views

Mechanism for palladium-catalysed spirocyclisation of conjugated diene

I'm trying to work out the catalytic cycle for the following process: I gather that the palladium will be reduced from Pd(II) to Pd(0) in the process and that the 1,4-benzoquinone is a redoxidant. ...
20
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1answer
820 views

Carbometalation of alkenes

Alkynes are capable of undergoing carbometalation, e.g. with organocopper reagents: Why don't the corresponding alkenes undergo analogous carbometalation reactions? Is β-elimination the issue?
6
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1answer
79 views

Selective transfer of least/most stable anion from organometallic reagents

When heterocuprate reagents participate in conjugate addition, the least stable anion is transferred from copper to the electrophile: On the other hand, palladium-catalysed cross-coupling reactions ...
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0answers
111 views

Ene-yne metathesis product

In the ene-yne metathesis how to know which product will form predominately, as the mechanisms to both are plausible?