Reading a scheme

Start with the conditions. A strong base, an acid, a metal, a peroxide: the reagent line narrows the reaction type before you look at a single bond.
Find what changed. Compare starting material and product atom by atom: which bond formed, which left, and whether the carbon count grew.
Substitution vs. elimination vs. addition is a bookkeeping question: same number of σ bonds, fewer, or more.
Mechanism follows structure. A tertiary or benzylic center with a weak nucleophile points to a cation; a primary center with a strong nucleophile does not.
Every example here is a real reaction with a real citation. The yields are the authors’ own.

Dehydration of alcohols

7 real reactions from the literature, on secondary alcohols, allylic alcohols, tertiary alcohols and halohydrins. Each scheme shows starting materials, conditions and products, with the yield and reference where the source reports them.

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