Yayik, NihanPérez Bosch, MariaMolins i Grau, EliesBosch Cartes, JoanAmat Tusón, Mercedes2021-02-012021-02-012021-01-151420-3049https://hdl.handle.net/2445/173571A synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3'-oxindole] framework present in a large number of oxindole alkaloids, with a cis H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an E-ethylidene substituent at C-20, is reported. The key steps of the synthesis are the generation of the tetracyclic spirooxindole ring system by stereoselective spirocyclization from a tryptophanol-derived oxazolopiperidone lactam, the removal of the hydroxymethyl group, and the stereoselective introduction of the E-ethylidene substituent by acetylation at the -position of the lactam carbonyl, followed by hydride reduction and elimination. Following this route, the 21-oxo derivative of the enantiomer of the alkaloid 7(S)-geissoschizol oxindole has been prepared.15 p.application/pdfengcc-by (c) Yayik, Nihan et al., 2021http://creativecommons.org/licenses/by/3.0/esAlcaloidesEnantiòmersCompostos heterocíclicsSíntesi orgànicaAlkaloidsEnantiomersHeterocyclic compoundsOrganic synthesisinfo:eu-repo/semantics/article7059652021-02-01info:eu-repo/semantics/openAccess33467493