132960-14-6Relevant articles and documents
Enantioselective Total Syntheses of (R)- A nd (S)-Naphthotectone, and Stereochemical Assignment of the Natural Product
Guerrero-Vásquez, Guillermo A.,Galarza, Flávia A. D.,Molinillo, José M. G.,Andrade, Carlos Kleber Z.,Macías, Francisco A.
, p. 1599 - 1604 (2016)
Both isomers of naphthotectone, an isoprenoid quinone from Verbenaceae Tectona grandis possessing interesting biological activities, were enantioselectively obtained by two different synthetic routes in which the carbon side-chain of the naphthoquinone core was introduced using either a Sonogashira or a Heck coupling reaction. In both cases, the naphthoquinone core of the final products was obtained by a late-stage anodic treatment. (R)-Naphthotectone was obtained in six steps from leuconaphthazarin with an overall yield of 38 % and an enantiomeric excess of 86 %. This compound was found to have the same absolute configuration as the natural product at its C-3′ stereogenic center. (S)-Naphthotectone was obtained in five steps from leuconaphthazarin with an overall yield of 36 % and an enantiomeric excess of 80 %. Naphthotectone was synthesized in both racemic and enantioenriched forms by two different synthetic strategies using Pd coupling reactions and anodic treatment as key steps. The stereochemistry of the natural product has been assigned.
An efficient synthesis of the 1,6-dioxaspiro[4.4]nonan-2-one motif of the immunosuppressive triterpenoid Phainanoid F
Zhang, Chen-Lu,Nan, Fa-Jun
, p. 4357 - 4359 (2017)
We describe an efficient synthesis of the 1,6-dioxaspiro[4.4]nonan-2-one motif of the immunosuppressive triterpenoid Phainanoid F and its C4 epimer. A furan oxidative spirocyclization for constructing the spiro center was used as the key step. Other important reactions involved Sharpless asymmetric dihydroxylation, Weinreb ketone synthesis and Yamaguchi esterfication. The synthesis was achieved in 11 linear steps with 17.3% overall yield.
Asymmetric dihydroxylation of esters and amides of methacrylic, tiglic, and angelic acid: No exception to the sharpless mnemonic!
Weber, Fabian,Brückner, Reinhard
, p. 2428 - 2449 (2015)
Literature findings on the facial selectivity of the Sharpless asymmetric dihydroxylation (SAD) of isobutyl angelate are contradictory and partly in conflict with the Sharpless mnemonic. We systematically screened the SAD of esters and amides of angelic, tiglic, and methacrylic acid. Enantiocontrol arose in 14 of the 15 reactions, culminating at 99 % ee for the Weinreb amide of tiglic acid. The absolute configurations of all the nonracemic products were established by (stereo)chemical correlations. Without exception, they conform to the Sharpless mnemonic.
An iron-catalyzed hydroalkylation reaction of α,β-unsaturated ketones with ethers
Lan, Yun,Fan, Pei,Liu, Xiao-Wei,Meng, Fei-Fan,Ahmad, Tanveer,Xu, Yun-He,Loh, Teck-Peng
supporting information, p. 12353 - 12356 (2017/11/20)
A general strategy for the hydroalkylation of vinyl ketones using ethers catalyzed by an iron catalyst is described. This catalytic method permits direct transformation of easily accessible and abundant precursors into highly substituted, structurally diverse and functionally concentrated products.