HCN and CN – in synthesis Increasing carbon chain length.

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HCN and CN in synthesis Increasing carbon chain length

Transcript of HCN and CN – in synthesis Increasing carbon chain length.

Page 1: HCN and CN – in synthesis Increasing carbon chain length.

HCN and CN– in synthesis

Increasing carbon chain length

Page 2: HCN and CN – in synthesis Increasing carbon chain length.

Reaction of haloalkanes with CN–

• RBr + CN– RCN + Br–

Reaction of carbonyl compounds with HCN:

• Aldehydes: RCHO + HCN RCH(CN)COH

• Ketones: RCOR’ + HCN RCR’(CN)COH

Formation of C–CN

Page 3: HCN and CN – in synthesis Increasing carbon chain length.

Haloalkane nitrile

Reagents and conditions

•CN– ions, e.g. KCN(aq) in ethanol solvent

Mechanism:

• Nucleophilic substitution

charge

lone pair

C–C bond forms

Page 4: HCN and CN – in synthesis Increasing carbon chain length.

Carbonyl nitrile

Reagents and conditions

• CN– ions in dilute acid, e.g. KCN(aq)/H2SO4(aq)

Mechanism:

• Nucleophilic addition

charge

lone pair

C–C bond forms

Page 5: HCN and CN – in synthesis Increasing carbon chain length.

Nitriles in synthesis

Reduction amines

• H2 and Ni catalyst

Acid hydrolysis carboxylic acids

• Aqueous acid, H+/H2O, e.g. HCl(aq)

aminenitrile

carboxylic acidnitrile