| abstract |
A process for the cyclopropanation of a substituted alkene, comprising the reaction of the alkene with a carbenoide, generated from dibromomethane and a tri-(C2 - C8)-alkyl aluminium compound, in the presence of a catalytic amount of a metal compound selected from the group consisting of Lewis acids, metallocenes and metal carbonyl complexes. The process advantageously uses transition metal compounds as catalysts and the dibromomethane can be recovered. The process is especially useful for the preparation of ingredients for the flavour and fragrance industry. |