HIGHLY STEREOSELECTIVE ROUTE TO (E)-ALLYL AMINES VIA VINYLTRI-N-BUTYLPHOSPHONIUM SALTS (SCHWEIZER REACTION)

The reaction of vinyltri-n-butylphosphonium salts, aldehydes and sodiophthalimide in THF [tetrahydrofuran] gave good yields of the allylic phthalimides with high E stereoselectivity (75-100%). The use of the vinyltriphenylphosphonium salts (Schweizer reaction) gave the allyl phthalimide with the Z isomer predominating. A study of the phthalimide cation and the effect of added lithium salt showed some reversal in the olefin geometry but in general the selectivity was only 3:1.