chemistry

Trofimov reaction

Trofimov reaction is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Trofimov reaction rather than just read about it. In short: In organic chemistry, the Trofimov reaction is a reaction used to synthesize 2,3-disubstituted pyrroles from ketoximes and acetylene using the superbase medium potassium hydroxide and dimethyl sulfoxide. The reaction is named after Boris Trofimov who first reported it in the 1970's.

Key takeaways

Trofimov reaction belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Trofimov reaction to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Trofimov reaction from memory before moving on to harder problems.

Reference excerpt

In organic chemistry, the Trofimov reaction is a reaction used to synthesize 2,3-disubstituted pyrroles from ketoximes and acetylene using the superbase medium potassium hydroxide and dimethyl sulfoxide. The reaction is named after Boris Trofimov who first reported it in the 1970's.

Mechanism

The mechanism begins with the deprotonation of the ketoxime by potassium hydroxide. The negative charge on the oxygen can then attack the acetylene. This forms the O-vinylketoxime which can tautomerize to a vinyl hydroxylamine. The molecule then undergoes a [3,3]-sigmatropic rearrangement to from an aldehyde-imine intermediate. The lone pair on the imine can then attack the carbonyl. Water is then lost forming an alkene. The final pyrrole is then formed by a [1,3] sigmatropic rearrangement.

Synthetic Applications The Trofimov reaction is a powerful reaction for building pyrroles in total synthesis. The starting ketoxime can be prepared simply by condensing hydroxylamine on a ketone. Starting from a ketone allows for a wide range of starting materials as ketones are one of the most common functional groups in organic chemistry. The condensation reaction can be shown below:

After the condensation, the pyrrole formation can proceed as normal. The Trofimov reaction can produce both N-H and N-vinyl pyrroles depending on the reaction conditions used. The N-vinyl pyrrole can be formed by the deprotonation of the pyrrole nitrogen which then attacks a second acetylene molecule. In general, higher temperatures, pressures, and higher concentrations of base favor the formation of the N-vinyl product.

Examples The Trofimov reaction was used to build N-vinylpyrrolocholestene. Starting from 5-Cholesten-3-one, hydroxylamine was condensed onto the ketone, forming the intermediate ketoxime. The ketoxime was then reacted with KOH and acetylene in DMSO at high temperature and pressure. Only one regioisomer was observed. In this case, the reaction conditions were sufficient to form the N-vinyl pyrrole2-mesityl-3-methylpyrrole was synthesized in 2004 via the Trofimov reaction. The reaction of the ketoxime with acetylene yielded a mixture of products with the primary one being the N-H pyrrole. Small amounts of the N-vinyl product were also observed as well as O-vinylketoxime. The N-vinyl product was then used in the synthesis of a new BODIPY.

Variations In 2005 a version of the Trofimov reaction was reported where both the hydroxylamine condensation and pyrrole formation occur in one pot. This variation uses the hydroxylamine HCl salt rather than hydroxylamine and sodium bicarbonate to perform the condensation onto a ketone. After the condensation, the reaction is warmed to 100 °C and the atmosphere in the flask is changed to acetylene. KOH is then added to form the pyrrole.

References

Illustrations

Worked examples

Example 1 — a first encounter with Trofimov reaction

Start with the simplest possible case. Write down what Trofimov reaction claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Trofimov reaction before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Trofimov reaction ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Trofimov reaction

In research: Trofimov reaction appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Trofimov reaction in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Trofimov reaction is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ring forming reactions, so understanding it makes those chapters shorter.
In everyday life: Look for Trofimov reaction outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Trofimov reaction in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Trofimov reaction means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Trofimov reaction out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Trofimov reaction in simple terms?

Why does Trofimov reaction matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Trofimov reaction?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Trofimov reaction.