6 documents found, page 1 of 1
Oxidation of mono-phenols to para-benzoquinones: a comparative study
Uliana,Marciana P.; Vieira,Ygor W.; Donatoni,Maria Carolina; Corrêa,Arlene G.; Brocksom,Ursula; Brocksom,Timothy J.The oxidation of mono-phenols to para-benzoquinones is of continuing interest due to the existence of numerous natural products containing this structural unit. The chemical reactivity of para-benzoquinones is also noteworthy, as oxidants and dienophiles in the Diels-Alder reaction. We have used for quite some time now, molecular oxygen and catalysis with [CoII(salen)] as the oxidation procedure, but felt the n...
A síntese dos sesquiterpenos baquenolidas
Brocksom,Timothy John; Brocksom,Ursula; Constantino,Maurício G.The bakkenolide group of sesquiterpenes has been a focal point of synthetic efforts amongst several research laboratories all linked to our common origins at the Chemistry Institute at the State University in São Paulo. In this review we would like to present a historical perspective of this research, with unpublished background information, and a definitive retrosynthetic analysis of these molecules. This chem...
A concise synthesis of the 1,6-disubstituted eudesmane sesquiterpene carbon ske...
Vieira,Ygor Willian; Nakamura,Joanita; Finelli,Fernanda Gadini; Brocksom,Ursula; Brocksom,Timothy JohnWe report a synthesis of the 1,6-disubstituted eudesmane sesquiterpene carbon skeleton, based upon a multicomponent Diels-Alder reaction.
The enantioselective synthesis of (R)-(+)-6-isopropenyl-3-methyl-2-cycloheptenone
Brocksom,Timothy J.; Brocksom,Ursula; Barbosa,Fernanda P.(R)-(+)-6-isopropenyl-3-methyl-2-cycloheptenone is synthesized from (R)-(-)-carvone by reduction and trialkylsilyl-enolether formation, cyclopropanation with methylene iodide and diethylzinc, followed by a Saegusa type oxidation with ferric chloride and finally dehydrochlorination with base. The title compound is obtained in five steps and 38% overall yield, being a useful chiron for guaiane sesquiterpene natur...
A reação de metátese de olefinas: reorganização e ciclização de compostos orgân...
Frederico,Daniel; Brocksom,Ursula; Brocksom,Timothy JohnThe olefin metathesis reaction allows the exchange of complex alkyl units between two olefins, with the formation of a new olefinic link and a sub-product olefin usually ethylene. This reaction has found extensive application in the last ten years with the development of the Grubbs and Schrock catalysts, in total synthesis of complex organic molecules, as opposed to the very important use in the petrochemical i...
The Diels-Alder reaction: an update
Brocksom,Timothy John; Nakamura,Joanita; Ferreira,Maria Lúcia; Brocksom,UrsulaThe last ten years have seen an explosive growth in synthetic applications of the Diels-Alder reaction, principally the intramolecular (IMDA) reaction but also the transannular (TADA) version. In this review we present these developments with special emphasis on the synthetic concepts and the experimental results and include related theoretical studies.