CHIMIE DES FRAGRANCES. PARTIE II : SYNTHESE DE LA g-IONONE ET DES CIS- ET TRANS-g-IRONES

François LEYENDECKER et Marie-Thérèse COMTE
 

A tandem1,4-addition functionnalisation reaction and a chemo- and regioselective olefination reaction are the key steps. This methodology afforded pure cis-g-irone in 4 steps in 11.6 % overall yield.







Reagents : a) i. Me2CuLi, Et2O; ii. a-Phenylsulfoxyl methyl acrylate ; iii. heat, toluene, CaCO3; b) Zn, CH2Br2, TiCl4, CH2Cl2; c) NaOH, toluene, 60°C; d) 2 MeLi, Et2O
 
 

It's a very good and short synthesis, with a low of stereoselectivity and it is not enantioselective.