I regard it as a great honour to be able to speak to you at this opening ceremony of the Symposium on The Chemistry of Natural Products. I would like to express my sincere and heartfelt thanks to the Australian Academy of Science, and especially to the Organizing Committee, for the invitation which they extended to me and which I accepted with great pleasure. This is my first visit to Australia...

Biocatalytic procedures can circumvent some of the drawbacks that classical methodologies present in chemical synthesis. One example is shown by the Baeyer-Villiger (BV) reaction, a process discovered more than 100 years ago that consists in the nucleophilic insertion of one atom of oxygen in the adjacent position of a carbonyl moiety affording esters or lactones. This reaction proceeds using p...

We report a peptide-based catalyst that can strongly influence the regio- and enantioselectivity of the Baeyer-Villiger (BV) oxidation of cyclic ketones bearing amide, urea, or sulfonamide functional groups. Both types of selectivity are thought to arise from a catalyst-substrate hydrogen-bonding interaction. Furthermore, in selected cases, the reactions exhibit the hallmarks of parallel kineti...

Limonoids are highly oxygenated C13α-triterpenes and common secondary metabolites. Several hundred congeners have been isolated to date. The first total synthesis of (±)-limonin, the flagship congener of the limonoids, is now reported and features 1) a tandem radical cyclization generating the BCD ring system with the C13α configuration that is essential to the limonoids and a Robinson annulati...

Catalytic enantioselective Baeyer-Villiger (BV) oxidations of racemic and meso cyclic ketones were achieved in the presence of chiral N,N'-dioxide-Sc(III) complex catalysts. The BV oxidations of prochiral cyclohexanones and cyclobutanones afforded series of optically active ε- and γ-lactones, respectively, in up to 99% yield and 95% ee. Meanwhile, the kinetic resolution of racemic 2-arylcyclohe...

Reações de biocatálise foram realizadas em microplacas (200 μL) visando a utilização de substratos fluorogênicos (100 μmol L) para prospecção rápida de epóxido hidrolases (EHs) e Baeyer-Villiger monoxigenases (BVMOs) em microrganismos (células inteiras). Um protocolo final foi alcançado para EHs, com a detecção de 3 novas fontes enzimáticas (Agrobacterium tumefaciens, Pichia stipitis, Trichospo...

ABSTRACT This study investigates the substrate profile of cycloalkanone monooxygenase and 2-oxo-Δ3-4,5,5-trimethylcyclopentenylacetyl-coenzyme A monooxygenase, two recently discovered enzymes of the Baeyer-Villiger monooxygenase family, used as whole-cell biocatalysts. Biooxidations of a diverse set of ketones were performed on analytical scale: desymmetrization of substituted prochiral cyclobu...

A stereoselective synthesis of (+)-norrisolide is presented. This natural product belongs to a family of marine spongiane diterpenes the structure of which is characterized by a fused gamma-lactone-gamma-lactol ring system attached to a bicyclic hydrophobic core. Our studies led to the development of a expedient synthesis of such gamma-lactone-gamma-lactol motifs based on ring expansion of a fu...

A new and efficient strategy is described for carrying out the enantiospecific synthesis of monocarbocyclic terpenoids from (-)-sclareol (1). The key steps are the Grob scission of l l p toluenesulphonyloxydriman-7ct-ol (2) to give the tobacco seco-sesquiterpene 3 and the Baeyer-Villiger oxidation of 4-[(1'S, 2'S)-2'-formyl-2',6',6'-trimethylcyclohexyl]-2-butanone (4), derived from 3. The first...

The synthesis of 4-[18F]fluoroguaiacol (4-[18F]fluoro-2-methoxyphenol) has been achieved in no-carrier-added form starting from 2-methoxy-4-nitrobenzaldehyde, using nucleophilic aromatic substitution by [18F]fluoride followed by Baeyer-Villiger oxidation of the benzaldehyde to the phenol. Demethylation with boron tribromide gave 4-[18F]fluorocatechol (1,2-dihydroxy-4-[18F]fluorobenzene) with an...