- Enantioselective Total Syntheses of (R)- A nd (S)-Naphthotectone, and Stereochemical Assignment of the Natural Product
-
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.
- Guerrero-Vásquez, Guillermo A.,Galarza, Flávia A. D.,Molinillo, José M. G.,Andrade, Carlos Kleber Z.,Macías, Francisco A.
-
supporting information
p. 1599 - 1604
(2016/04/05)
-
- Synthesis of the C7-C23 fragment related to iriomoteolide-1a via B -alkyl suzuki-miyaura cross-coupling and indium-mediated aldehyde allylation
-
Synthesis of the C7-C23 fragment and its 18R,19S-diastereomer of iriomoteolide-1a has been accomplished from the C7-C12 allyl bromide, the C13-C16 vinyl iodide, and the C17-C23 alkyl iodide fragments. These fragments were assembled first by the B-alkyl Suzuki-Miyaura cross-coupling to give the C13-C23 intermediate. The latter, after being transformed into the C13 aldehyde, was coupled to the C7-C12 allyl bromide in the presence of indium powder in THF-H2O (1:1) at 70deg;C to the fully functionalized C7-C23 fragment with orthogonal protecting groups at C19 (PMB ether), and C9, C14, and C22 (TBS, TES, and TBS ethers, respectively). Formation of the characteristic six-membered C9/C13-hemiacetal ring has been demonstrated after global desilylation using pyridine-buffered HF.
- Liu, Yuanxin,Wang, Jian,Li, Huoming,Wu, Jinlong,Feng, Gaofeng,Dai, Wei-Min
-
scheme or table
p. 2184 - 2188
(2010/10/21)
-
- PYRIDIN-2-YL-AMINO-1,2,4-THIADIAZOLE DERIVATIVES AS GLUCOKINASE ACTIVATORS FOR THE TREATMENT OF DIABETES MELLITUS
-
Provided are compounds of Formula (I): wherein R2, R3, R13, L and D2 are as defined in the specification, which are useful in the treatment and/or prevention of diseases or disorders mediated by deficient levels of glucokinase activity or which can be treated by activating glucokinase including, but not limited to, diabetes mellitus, impaired glucose tolerance, IFG (impaired fasting glucose) and IFG (impaired fasting glycemia), as well as other diseases and disorders such as those discussed herein
- -
-
Page/Page column 132
(2009/05/29)
-
- THE CHIRAL SYNTHESIS OF BICYCLOMYCIN
-
The optically active bicyclomycin was succesfully synthesized in 17 steps from N,N'-diacetyl-anhydroglycine.
- Yoshimura, Juji,Yamaura, Masanori,Suzuki, Tsuneji,Hashimoto, Hironobu
-
p. 2157 - 2158
(2007/10/02)
-