Phenols can be protected (K2CO3, acetone) as their cyanomethyl ethers which can be cleaved by hydrogenation of the nitrile: Tetrahedron Lett., 34, 7567 (1993).
The Reformatsky-type reaction with cyclohexanone is more successful in the presence of a Zn/Ag couple than with the conventional Zn-Cu couple: Synth. Commun., 19, 2355 (1989). Good yields of ?-hydroxy nitriles have also been achieved from aldehydes and ketones using Zn and TMS chloride: Tetrahedron Lett., 31, 2205 (1990). The condensation with aldehydes can also be mediated by active Ni: Tetrahedron Lett., 26, 155 (1985). The reaction with aldehydes in the presence of Zn and tri-n-butylphosphine gives ɑ?-unsaturated nitriles directly: Synth. Commun., 20, 3277 (1990).
