Acetylene → 4-Benzyl-2-iodomethylmorpholine

The starting material for use in processes (a), (b) and (h) in which A is a vinylene radical may be prepared, as described in Example 1, by reaction of 4-benzyl-2-(toluene-p-sulphonyloxymethyl)morpholine and lithium iodide to give 4-benzyl-2-iodomethylmorpholine. This compound is then reacted with triphenyl phosphine to give 4-benzylmorpholin-2-ylmethyl triphenyl phosphonium iodide which is subsequently reacted with a base to form the corresponding phosphorane. This intermediate is reacted in situ with the appropriate substituted benzaldehyde to give 4-benzyl-2-(β-substituted phenylvinyl)-morpholine as a mixture of cis and trans isomers. These isomers are, if necessary, separated by chromatography, or by fractional crystallisation of an acid-addition salt, and if required this N-benzyl derivative is used to form other N-substituted starting materials. Thus reaction with an aryl or optionally substituted alkyl chloroformate gives the corresponding phenoxy- or alkoxy-carbonyl derivative, or reaction with cyanogen bromide gives the corresponding N-cyano derivative.