The first synthesis of the natural product (+)-mutisianthol was accomplished in 11 steps and in 21% overall yield from 2-methylanisole. The synthesis of its enantiomer was also performed in a similar overall yield. The absolute configuration of the sesquiterpene (+)-mutisianthol was assigned as (1S,3R). Key steps in the route are the asymmetric hydrogenation of a nonfunctionalized olefin using chiral iridium catalysts and the ring contraction of 1,2-dihydronaphthalenes using thallium(III) or iodine(III). The target molecules show moderate activity against the human tumor cell lines SF-295, HCT-8, and MDA-MB-435.

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In this work we describe the cyclofunctionalization of eleven differently substituted alkenyl-beta-dicarbonyl compounds, employing three electrophilic reagents, namely, iodine, p-methoxyphenyltellurium trichloride, and phenylselenenyl bromide. The reactions occur through the enolic form of the substrates, to afford the corresponding iodo-, telluro-, or selenocyclic enol ethers. Substrates bearing trisubstituted double bonds failed in reacting with the selenium and tellurium reagents. In general, beta-diketones reacted faster than beta-keto esters with the three studied electrophiles.

Recebido em 15/1/08; aceito em 27/2/08; publicado na web em 2/4/09The bioreduction of a series of substituted α-tetralones, carried out using Daucus carota root (carrot), afforded the corresponding homochiral α-tetralols in variable conversions (9 to 90%) and excellent enantiomeric excesses. Two of the assayed α-tetralones were resistant to the bioreduction conditions. The absolute configurations of four α-tetralols were assigned as being (S), by comparison to the (S)-enantiomers obtained by kinetic resolution promoted by CALB-catalysed acetylation. Additionally, the new 5-methoxy-6-methyl-1-tetralone was synthesized in seven steps from 3-methylsalicylic acid.

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Terpenes U 0200 (+)-and (-)-Mutisianthol (I): First Total Synthesis, Absolute Configuration, and Antitumor Activity. -(BIANCO, G. G.; FERRAZ, H. M. C.; COSTA, A. M.; COSTA-LOTUFO, L. V.; PESSOA, C.; DE MORAES, M. O.; SCHREMS, M. G.; PFALTZ*, A.; SILVA, L. F. J.; J. Org. Chem. 74 (2009) 6, 2561-2566; Dep. Chem., Univ. Basel, CH-4056 Basel, Switz.; Eng.) -Mischke 32-181