| abstract |
In the prodn. of 3,3-dimethyl-4-pentenenitrile (I), acetaldehyde is reacted with isobutyraldehyde to give a dioxan cpd (II); this is hydrogenated (opt. in the presence of diluents and catalysts) to a diol (III), this is converted in a conventional manner into an ester of formula CH3CH(OR)C (CH3)2 CH2OR (IV) (where R is alkylsulphonyl or arylsulphonyl), and (IV) is reacted with HCN or metal cyanide in the presence of a base to give (I). In a variant of this process, (III) is converted into an ester (IV) in which R+R is CO, this is pyrolysed at 200-280 degrees C (opt. in the presence of a diluent), the resulting alkene (V) is converted into an ester of formula CH2=CH-C(CH3)2 CH2OR (VI) (where R is alkylsulphonyl or arylsulphonyl, and (VI) is reacted with a metal cyanide or with HCN/base to give (I). |