Synthesis of Natural and Unnatural Enantiomers of Goniofufurone and Its 7-Epimers from D-Glucose. Application of Palladium(II) - Catalyzed Oxycarbonylation of Unsaturated Polyols

All articles of this category 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.