Boreskov Institute of Catalysis SB RAS, Novosibirsk, Russia

KN-6PALLADIUM-CATALYZED AEROBIC OXIDATIONOF BIOMASS-BASED ALKENES AS A ROUTE TO VALUABLEFRAGRANCE AND PHARMACEUTICAL COMPOUNDSElena V. Gusevskaya, Luciana A. Parreira, Luciano MeniniUniversidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, BrazilFax: (+55)-31-3409570; e-mail: elena@ufmg.brThe functionalization of naturally occurring special olefins can provideoxygenated compounds valuable in the fine chemicals industry. For several years,we have been interested in oxidative transformations of terpenes and substituted allylbenzenes, which are easily available from biomass and represent an importantrenewable feedstock for pharmaceutical and flavor&fragrance industries. In thepresent communication, we will review our new and recently published results in thisfield.A palladium-catalyzed selective oxidation is one of the more versatile methods tointroduce an oxygen-containing functionality in organic molecules. These reactionsare especially attractive when molecular oxygen is involved as a final oxidant, whichis usually achieved by using CuCl 2 as co-catalyst (Wacker catalyst). However, theWacker process requires large amounts of chloride ions and acid to maintain acatalytic cycle; therefore, the system is highly corrosive and often causes theformation of chlorinated side products. Although the systems with various alternativehalide-free co-catalysts, such as Cu(OAc) 2 , heteropoly acids, nitrates, andbenzoquinone, have been intensively studied in attempts to reduce an environmentalimpact of these processes, the reoxidation of palladium(0) during the catalytic cycleunder more friendly conditions remains a critical challenge.We have studied the palladium catalyzed aerobic oxidations of a number ofterpenic (limonene, camphene, myrcene, linalool, dihydromyrcene, nerolidol, etc) andallyl aromatic (eugenol, safrole, estragole, etc) natural compounds and developedvarious efficient methods for the synthesis of industrially important oxygenatedproducts. A special attention has been given to chloride-free catalytic systems andthe systems in which palladium (II) chloride is used as the sole catalyst in theabsence of co-catalysts or stabilizing ligands.20