title: Lewis super-acid catalyzed cyclizations: a new route to fragrance compounds.
abstract: This review deals with the application of Lewis super acids such as Al(III), In(III), and Sn(IV) triflates and triflimidates as catalysts in the synthesis of fragrance materials. Novel catalytic reactions involving C-C and C-heteroatom bond-forming reactions, as well as cycloisomerization processes are presented. In particular, Sn(IV) and Al(III) triflates were employed as catalysts in the selective cyclization of unsaturated alcohols to cyclic ethers, as well as in the cyclization of unsaturated carboxylic acids to lactones. The addition of thiols and thioacids to non-activated olefins, both in intra- and intermolecular versions, was efficiently catalyzed by In(III) derivatives. Sn(IV) Triflimidates catalyzed the cycloisomerization of highly substituted 1,6-dienes to gem-dimethyl-substituted cyclohexanes bearing an isopropylidene substituent. The hydroformylation of these unsaturated substrates, catalyzed by a Rh(I) complex with a bulky phosphite ligand, selectively afforded the corresponding linear aldehydes. The olfactory evaluation of selected heterocycles, carbocycles, and aldehydes synthesized is also discussed.
authors.affiliation: Laboratoire de Chimie des Molécules Bioactives et des Arômes, Université de Nice-Sophia Antipolis, CNRS, UMR 6001, Institut de Chimie de Nice, Parc Valrose, F-06108 Nice Cedex 2.
authors.forename: Lydie
authors.initials: L
authors.lastname: Coulombel
authors.forename: Fanny
authors.initials: F
authors.lastname: Grau
authors.forename: Michel
authors.initials: M
authors.lastname: Weïwer
authors.forename: Isabelle
authors.initials: I
authors.lastname: Favier
authors.forename: Xavier
authors.initials: X
authors.lastname: Chaminade
authors.forename: Andreas
authors.initials: A
authors.lastname: Heumann
authors.forename: J Carles
authors.initials: JC
authors.lastname: Bayón
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Aguirre
authors.forename: Elisabet
authors.initials: E
authors.lastname: Duñach
mesh_terms: D000438:Alcohols / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods; D003500:Cyclization; D003512:Cyclohexanones / Q000737:chemistry*; D008698:Mesylates / Q000737:chemistry*; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry; D010476:Perfume / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000438:Alcohols; D002264:Carboxylic Acids; D003512:Cyclohexanones; D008698:Mesylates; D009942:Organometallic Compounds; D010476:Perfume; C518058:triflimide; C012077:trifluoromethanesulfonic acid