SYNTHESIS OF THE SEX PHEROMONE OF APPLE LEAFROLLER (Bonagota cranaodes)

Abstract

Apple is one of the most produced fruits in the world, and is mainly sold for in natura consumption. China, USA and Poland are the top three countries in apple production. In Brazil, 98% of the production is concentrated in the southern region. Bonagota cranaodes (Lepdoptéra: Tortricidae) is one of the main apple pests, it occurs year-round, at varying population densities, and its larvae effectively nestle among fruits and leaves and are difficult to control with insecticides. Besides the high potential of damage to the crop, the leafroller caterpillar exhibits resistance to insecticides, being necessary to increase the number of applications, increasing the cost of production, contaminating the environment, the producer and the consumer. The present work aims to synthesize the sexual pheromone of B. cranaodes – (3E,5Z)-dodecadienyl acetate. The synthetic route was performed in five steps: the first step consisted of a bromination reaction of 1-octyne with NBS and AgNO3, forming 1-bromooct-1-yne. This in turn was reduced to the alkene (Z) in a reaction with lindlar in hexane. In the third stage, a cross-coupling (Sonogashira reaction) was performed between 1-bromooct-1-ene and 3-butyn-1-ol in the presence of CuI and Pd(Ph3)4. Following this coupling, the triple bond at position 3 will be reduced with LiAlH4 in diglyme (generating the double with stereochemistry E). The last step consists of an acetylation reaction with acetic anhydride and pyridine. The synthesized products were confirmed by GC-MS and NMR techniques.