chemistry

Meyer–Schuster rearrangement

Meyer–Schuster rearrangement 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 Meyer–Schuster rearrangement rather than just read about it. In short: The Meyer–Schuster rearrangement is the chemical reaction described as an acid-catalyzed rearrangement of secondary and tertiary propargyl alcohols to α,β-unsaturated ketones if the alkyne group is internal and α,β-unsaturated aldehydes if the alkyne group is terminal. Mechanism The reaction proceeds by three major steps: (1) the rapid protonation of oxygen, (2) the slow, rate-determining step comprising the 1,3-shi…

Key takeaways

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

Reference excerpt

The Meyer–Schuster rearrangement is the chemical reaction described as an acid-catalyzed rearrangement of secondary and tertiary propargyl alcohols to α,β-unsaturated ketones if the alkyne group is internal and α,β-unsaturated aldehydes if the alkyne group is terminal.

Mechanism

The reaction proceeds by three major steps: (1) the rapid protonation of oxygen, (2) the slow, rate-determining step comprising the 1,3-shift of the protonated hydroxy group, and (3) the keto-enol tautomerism followed by rapid deprotonation. Formation of the unsaturated carbonyl compound is irreversible. Solvent is important and solvent caging is proposed to stabilize the transition state.

Rupe rearrangement The reaction of tertiary alcohols containing an α-acetylenic group does not produce the expected aldehydes, but rather α,β-unsaturated methyl ketones via an enyne intermediate. This alternate reaction is called the Rupe reaction, and competes with the Meyer–Schuster rearrangement in the case of tertiary alcohols.

Use of catalysts The traditional Meyer–Schuster rearrangement is induced by strong acids, which introduces competition with the Rupe reaction if the alcohol is tertiary. Milder conditions are possible with transition metal-based and Lewis acid catalysts (for example, Ru- and Ag-based catalysts). Microwave-radiation with InCl3 catalyst to give excellent yields with short reaction times and good stereoselectivity.

Use in organic synthesis The Meyer–Schuster rearrangement has been used in several syntheses. ω-Alkynyl-ω-carbinol lactams convert into enamides using catalytic PTSA α,β-Uunsaturated thioesters have been prepared from γ-sulfur substituted propargyl alcohols. 3-Alkynyl-3-hydroxyl-1H-isoindoles rearrange under mildly acidic conditions to the α,β-unsaturated carbonyl compounds. The synthesis of a part of paclitaxel exploits this rearrangement for a diastereomerically-selective route to the E-alkene.

The step shown above had a 70% yield (91% when the byproduct was converted to the Meyer-Schuster product in another step). The authors used the Meyer–Schuster rearrangement because they wanted to convert a hindered ketone to an alkene without destroying the rest of their molecule.

History The reaction is named after Kurt Meyer and Kurt Schuster. Reviews have been published by Swaminathan and Narayan,

Applications Used in Butaclamol synthesis.

References

Illustrations

Worked examples

Example 1 — a first encounter with Meyer–Schuster rearrangement

Start with the simplest possible case. Write down what Meyer–Schuster rearrangement 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 Meyer–Schuster rearrangement 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 Meyer–Schuster rearrangement 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 Meyer–Schuster rearrangement

In research: Meyer–Schuster rearrangement 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 Meyer–Schuster rearrangement 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: Meyer–Schuster rearrangement is common in secondary-school and first-year university syllabi. It links to neighbouring topics Name reactions, Rearrangement reactions, so understanding it makes those chapters shorter.
In everyday life: Look for Meyer–Schuster rearrangement 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 Meyer–Schuster rearrangement in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Meyer–Schuster rearrangement 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 Meyer–Schuster rearrangement out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Meyer–Schuster rearrangement in simple terms?

Why does Meyer–Schuster rearrangement 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 Meyer–Schuster rearrangement?

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 Meyer–Schuster rearrangement.