Organic Chemistry Mechanism Solver

How steps, arrows and products are shown

Each mechanism is split into numbered steps. A step has a short title, such as "Protonation of the alkene" or "Backside attack by methoxide", and a drawing of the species involved. Curved arrows start at the electrons that move (a lone pair or a bond) and point to where they end up, so you can read a step the same way you would draw it on an exam.

Intermediates carry their formal charges, so carbocations, oxonium ions, enolates and tetrahedral intermediates are easy to spot. Where a reaction sets stereochemistry, the drawings keep wedges and dashes. The last panel shows the final product, and you can turn the written step descriptions on or off.

Reactions it covers

The solver holds more than 150 reagent-specific mechanisms. Representative classes:

• Substitution and elimination SN1, SN2, E1 and E2 on alkyl halides, including carbocation rearrangements, Gabriel synthesis and Grignard formation.
• Alkene additions HX, X₂, halohydrin formation, acid-catalyzed hydration, oxymercuration, hydroboration, epoxidation, dihydroxylation, ozonolysis and catalytic hydrogenation.
• Alkynes HX and X₂ addition, Lindlar and dissolving-metal reductions, and alkyne formation from dihalides.
• Alcohols conversion to alkyl halides (HX, SOCl₂, PBr₃, HCl/ZnCl₂), tosylation, acid-catalyzed dehydration, oxidation and silyl protection.
• Aldehydes and ketones hydride reductions, Grignard addition, imine and enamine formation, aldol reactions, keto–enol tautomerization and the haloform reaction.
• Carboxylic acid derivatives acid chloride to ester or amide, Fischer esterification, ester hydrolysis and DCC coupling.
• Aromatic chemistry electrophilic aromatic substitution (halogenation, nitration, sulfonation, Friedel–Crafts), nitro group reduction and diazonium reactions.
• Pericyclic the Diels–Alder reaction.

What it does not do

The solver applies curated, human-reviewed mechanisms. It does not calculate a pathway from first principles, so it will not invent a mechanism for a reagent it does not know, and it does not estimate rates, yields or energies.

It works on one drawn reactant and one reagent at a time, and it shows the major textbook pathway. Minor products, solvent and temperature effects, and competing pathways appear only where the reagent itself encodes them, for example cold versus hot KMnO₄. Treat it as a way to check and study your reasoning, not as a replacement for it.

Without a Pro subscription you can preview the opening of any mechanism: the first step, or the first two steps of longer mechanisms. Pro unlocks every step and the final product.

If no mechanism appears

• Check the functional group. A reagent only runs on the groups it reacts with. NaBH₄ reduces an aldehyde or a ketone, so it returns nothing for an alkene or an ester.
• Draw the whole molecule. Include charges and every heteroatom. A missing oxygen or a stray fragment changes which groups are detected.
• Pick the exact reagent variant. Conditions such as heat, a peroxide, or the workup are separate entries in the reagent list.
• Simplify the substrate. If a large molecule fails, try the same functional group on a smaller one to see the pattern first.
• Confirm the product. The Reaction Solver predicts products for the same reactant and reagent, which helps tell "no reaction" from "no mechanism yet".