Base-catalysed prototropic isomerization. Part V. A novel method for the preparation of enamines

Abstract

Allylamines (I) have been isomerized cleanly to prop-1-enylamines (II) on a dispersion of potassium amide on alumina. (CH₂CH·CH₂)_xR_3–xN →(CH₃·CHCH_xR_3–xN, (x= 1, 2, 3) The method has many advantages over older ones for the preparation of some of the lower enamines, and for the preparation of di- and tri-(prop-1-enyl)amines (II; x= 2 and 3). The yields are good and the recovery of the product of isomerization is easier than with older techniques. However, the method is not general and is useful only for the preparation of propenylamines.