Octet

Octet / Reactions

Lindlar Reduction (Alkyne → cis-Alkene)

Lindlar Reduction (Alkyne → cis-Alkene) (Reduction Addition.) Converts CC#CC to C/C=C\C using H₂, Lindlar catalyst (Pd/CaCO₃/Pb). Stereochemistry: Syn addition → cis-alkene.

Addition

Reaction details

Name

Lindlar Reduction (Alkyne → cis-Alkene)

Type

Addition

Subtype

Reduction

Starting Material

CC#CC

Product

C/C=C\C

Reagents

  • H₂

  • Lindlar catalyst (Pd/CaCO₃/Pb)

Mechanism
  1. Smiles

    CC#CC

    Description

    2-Butyne (internal alkyne)

  2. Smiles

    C/C=C\C

    Description

    Partial reduction to cis-alkene

Stereochemistry

Syn addition → cis-alkene

Tips

  1. Lindlar catalyst is "poisoned" - stops at alkene

  2. Lead (Pb) deactivates catalyst to prevent over-reduction

  3. For trans-alkene, use dissolving metal reduction

Related Reactions

  • dissolving-metal-reduction

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Reactions

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Source collection

SN2 with Hydroxide

SN2 with Hydroxide (SN2 Substitution.) Converts CCBr to CCO using NaOH, KOH. Conditions: Polar aprotic solvent in DMSO, DMF, or acetone. Stereochemistry: Inversion of configuration (Walden inversion).

Substitution

SN2 with Cyanide

SN2 with Cyanide (SN2 Substitution.) Converts CCI to CC#N using NaCN, KCN. Conditions: Polar aprotic solvent in DMSO or DMF. Stereochemistry: Inversion of configuration.

Substitution

SN1 Solvolysis

SN1 Solvolysis (SN1 Substitution.) Converts CC(C)(C)Br to CC(C)(C)O using H₂O. Conditions: Polar protic solvent, heat in Water or aqueous ethanol. Stereochemistry: Loss of stereocontrol (planar carbocation attacked from either face → racemization if chiral ce...

Substitution

SN2 with Tosylate Leaving Group

SN2 with Tosylate Leaving Group (SN2 Substitution.) Converts CCOS(=O)(=O)c1ccc(C)cc1 to CCN=[N+]=[N-] using NaN₃. Conditions: Polar aprotic solvent.

Substitution

SN2 with Azide

SN2 with Azide (SN2 Substitution.) Converts CCBr to CCN=[N+]=[N-] using NaN₃. Conditions: Polar aprotic solvent.

Substitution

E2 Elimination

E2 Elimination (E2 Elimination.) Converts CC(Br)CC to CC=CC using KOtBu, NaOEt, NaOH (conc.). Conditions: Strong base, heat in t-BuOH or EtOH. Stereochemistry: Anti-periplanar geometry required. E/Z depends on which H is removed..

Elimination

Study guides

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