作者:Porino Va、William R. Roush
DOI:10.1016/j.tet.2007.02.058
日期:2007.6
Four amphidinolide E stereoisomers, amphidinolide E (1), 2-epi-amphidinolide E (2), 19-epi-amphidinolide E (3), and 2-epi-19-epi- amphidinolide E (4), have been synthesized via the judicious union of aldehyde 5, allylsilanes 7 or 8, acids 9 or 10, and vinylstannane 6. The C19 stereocenters of the C19 epimeric allylsilanes 7 and 8 were introduced via crotylboration reactions early in the synthesis. [3+2] Annulation reactions of aldehyde 5 with allylsilanes 7 and 8 were employed to set the core tetrahydrofuran units of 1-4. Finally, the C2 stereo-center was installed by esterification using acid 9, without incident, or with acid 10, in which case an unexpected and completely stereoselective inversion of C2 occurs. (C) 2007 Elsevier Ltd. All rights reserved.