Résumé
Lithiated anions derived from (alkenyl) pentamethyl phosphoric triamides as homoenolate equivalents are used in the reaction with halogenated acetal and ketal giving regioselectively the gamma-alkylation adducts. Chemoselective acidic hydrolysis of the enephosphoramide moiety in the presence of acetal or ketal groups leads to expected carbonyl products, key intermediates in the synthesis of natural compounds. The synthetic potential of the presented strategy is illustrated by stereoselective synthesis of two pheromones namely, 9-oxo-2(E)-decenoic acid 1 from queen substance and 10-hydroxy-2(E)-decenoic acid 2 from royal jelly of honeybee Apis mellifera. (C) 2010 Elsevier B.V. All rights reserved.