What is an aqueous workup?

For an aqueous workup of most organic compounds this will involve: Diluting the reaction mixture with a solvent for workup (this is the organic layer). Some of the byproducts generated during the reaction will be neutralized or removed by dissolving in the aqueous layer.

Which is the rate determining step in Stille coupling?

transmetalation step
The CO can coordinate to the palladium catalyst (9) after initial oxidative addition, followed by CO insertion into the Pd-R1 bond (10), resulting in subsequent reductive elimination to the ketone (12). The transmetalation step is normally the rate-determining step.

Which catalysts are common in the Stille coupling reaction?

Catalyst design The Stille reaction uses a palladium catalyst. It can use an 18- or 16-electron Pd (0) complex as a source of the catalyst, such as Pd(PPh3)4, Pd(dba)2. Then through ligand dissociation, it can be formed into a 14-electron Pd (0), the active catalyst.

How do you remove tin from a reaction?

Workup for Removing Tin Byproducts

1. Byproducts of tin based reactions such as Bu3SnBr can be removed by treatment with AlMe3 to create the nonpolar Bu3SnMe or NaOH to create the polar Bu3SnOH.
2. Filter through a mixture of KF/Celite.
3. Dilute rxn with suitable organic solvent.

When was the Stille coupling reaction first reported?

Stille coupling reactions, first reported in 1981, were the earliest examples of efficient one-step cross-coupling protocols for the synthesis of modified nucleosides. Despite the mild reaction conditions, the main limitation is the toxicity of the hydrophobic and water insoluble tin reagents utilized during the reaction.

Are there any drawbacks to Stille coupling chemistry?

Well-elaborated methods allow the preparation of different products from all of the combinations of halides and stannanes depicted below. The main drawback is the toxicity of the tin compounds used, and their low polarity, which makes them poorly soluble in water.

Why is the Stille reaction common in organic synthesis?

Due to these organotin reagent’s stability to air and their ease of synthesis, the Stille reaction became common in organic synthesis. The mechanism of the Stille reaction has been extensively studied.

How many papers were published on coupling reactions?

By the mid-1980s, over 65 papers on the topic of coupling reactions involving tin had been published, continuing to explore the substrate scope of this reaction.