An Expeditious Enantiospecific Total Synthesis of (-)-Crassalactone C
作者:Kavirayani Prasad、S. Kumar
DOI:10.1055/s-0032-1318303
日期:——
A concise and expeditious approach for the totalsynthesis of bioactive styryllactone (–)-crassalactone C is presented from tartaric acid. The main features of the synthesis include the desymmetrization of dimethylamide of tartaric acid and the effective use of cinnamoyl ester as a protecting group as well as a reactant in the ring-closing metathesis reaction. A concise and expeditious approach for
(+) and (−)-Goniofufurones, (+) and (−)-8-epi-goniofufurones have been synthesized from d-(−) and l-(+)-tartaric acids by the addition of ethyl lithiopropiolate to a chiral aldehyde intermediate as a key step, in which LDA is the best base compared to n-BuLi plus Lewis acid YCl3 (cat.).
Synthesis of Natural and Unnatural Enantiomers of Goniofufurone and Its 7-Epimers from D-Glucose. Application of Palladium(II) - Catalyzed Oxycarbonylation of Unsaturated Polyols
作者:Tibor Gracza、Volker Jäger
DOI:10.1055/s-1994-25694
日期:——
Syntheses of 3,6-anhydro-2-deoxy-7-phenylglyconolactones (+)-1 and (+)-2 with D- and L-glycero-D-ido configuration, respectively, as well as of their enantiomers (-)-1 and (-)-2, from D-glucose are presented. The key steps are, (i) phenylmagnesium bromide additions to C1 or C5 of glucose-derived aldehydes 7 and 10, respectively, and (ii), palladium (II)-catalyzed oxycarbonylation of intermediate 1-phenyl-D- and -L-5-hexenitols 8/9 or 14/15. The syntheses proceed in 7 steps with 6% and 18% over-all yield for (+)-1/ (+)-2, and in 6 steps/ 11% and 16% for (-)-1/ (-)-2 ( from monoacetone glucose). The absolute configurations of goniofufurone (+)-1 and its 7-epimer (+)-2 thus established are in accord with those of all suggested biogenetic precursors and allowed, e.g., to propose the absolute configuration of (+)-goniopypyrone, a related cytotoxic, bicyclic styryllactone, and structures of potential biosynthetic intermediates not identified so far.
Goniofufurone: synthesis and absolute configuration
作者:Tony K. M. Shing、Hon-chung Tsui
DOI:10.1039/c39920000432
日期:——
The absolute configuration of natural goniofufurone is shown to be 2 by an unambiguous synthesis of its enantiomer 1 from D-glycero-D-gulo-heptono-γ-lactone involving an intramolecular Michael reaction as the key step.
Stereocontrolled syntheses of (-)-goniofufurone and (-)-8-epi-goniofufurone
作者:Tony K.M. Shing、Hon-Chung Tsui、Zhao-Hui Zhou
DOI:10.1016/s0040-4020(01)89441-2
日期:——
(acetylation, hydrolysis, deacetylation, glycol cleavage, Wittig reaction, and hydrolysis) into the γ-lactone 5 which underwent an intramolecular Michael reaction to yield (-)-goniofufurone 1. Likewise reactions of the monoacetate 12 gave (-)-8-epi-goniofufurone 3.