Matches in SemOpenAlex for { <https://semopenalex.org/work/W3100738191> ?p ?o ?g. }
Showing items 1 to 54 of
54
with 100 items per page.
- W3100738191 abstract "A central challenge in the synthesis of the antiangiogenic cortistatin A 3 is the stereocontrolled assembly of the cycloheptene ring. Shuji Yamashita and Masahiro Hirama of Tohoku University solved (J. Org. Chem. 2011, 76, 2408) this problem by the addition of the intermediate radical from the reduction of 1 in an intramolecular sense to the cyclohexenone of 1 to give 2. The starting point for the synthesis was the enantiomerically enriched enone 4, prepared from the Hajos-Parrish ketone. Alkylation gave 6, which was reduced, after some experimentation, selectively to the trans-fused ketone 7. Pd-mediated oxidation of the silyl enol ether derived from 7 gave the enone, which was homologated to the aldehyde 8 by way of the corresponding enol triflate. Condensation with dihydroresorcinol 9 delivered the triene 10, which was carried on the iodide 1. Unexpectedly, 1 readily epimerized at the indicated stereocenter, presumably by way of an equilibrating Claisen rearrangement. Fortunately, when the solid iodide was maintained at-30oC for 12 h, the desired diastereomer became dominant. The free radical reduction then proceeded smoothly to give 2. To introduce the pendant isoquinoline of the natural product, 2 was protected and oxidized to 11. Reduction of the thiocarbamate derived from the tertiary alcohol 13, with H atom transfer to the more open face of the intermediate free radical, then delivered 14. To oxidize 14 to the enone 15, the ketone was deprotonated, then exposed to the Mukaiyama reagent 15. Nucleophilic epoxidation followed by reduction, following the Nicolaou precedent, then set the stage for selective opening with dimethylamine, to complete the synthesis of (+)-cortistatin A 3." @default.
- W3100738191 created "2020-11-23" @default.
- W3100738191 creator A5022717028 @default.
- W3100738191 date "2015-01-08" @default.
- W3100738191 modified "2023-09-26" @default.
- W3100738191 title "The Yamashita/Hirama Synthesis of Cortistatin A" @default.
- W3100738191 doi "https://doi.org/10.1093/oso/9780190200794.003.0086" @default.
- W3100738191 hasPublicationYear "2015" @default.
- W3100738191 type Work @default.
- W3100738191 sameAs 3100738191 @default.
- W3100738191 citedByCount "0" @default.
- W3100738191 crossrefType "book-chapter" @default.
- W3100738191 hasAuthorship W3100738191A5022717028 @default.
- W3100738191 hasConcept C134195300 @default.
- W3100738191 hasConcept C146686406 @default.
- W3100738191 hasConcept C155647269 @default.
- W3100738191 hasConcept C161790260 @default.
- W3100738191 hasConcept C164361826 @default.
- W3100738191 hasConcept C178790620 @default.
- W3100738191 hasConcept C185592680 @default.
- W3100738191 hasConcept C2777495281 @default.
- W3100738191 hasConcept C2777738585 @default.
- W3100738191 hasConcept C2778491686 @default.
- W3100738191 hasConcept C2779746879 @default.
- W3100738191 hasConcept C71240020 @default.
- W3100738191 hasConceptScore W3100738191C134195300 @default.
- W3100738191 hasConceptScore W3100738191C146686406 @default.
- W3100738191 hasConceptScore W3100738191C155647269 @default.
- W3100738191 hasConceptScore W3100738191C161790260 @default.
- W3100738191 hasConceptScore W3100738191C164361826 @default.
- W3100738191 hasConceptScore W3100738191C178790620 @default.
- W3100738191 hasConceptScore W3100738191C185592680 @default.
- W3100738191 hasConceptScore W3100738191C2777495281 @default.
- W3100738191 hasConceptScore W3100738191C2777738585 @default.
- W3100738191 hasConceptScore W3100738191C2778491686 @default.
- W3100738191 hasConceptScore W3100738191C2779746879 @default.
- W3100738191 hasConceptScore W3100738191C71240020 @default.
- W3100738191 hasLocation W31007381911 @default.
- W3100738191 hasOpenAccess W3100738191 @default.
- W3100738191 hasPrimaryLocation W31007381911 @default.
- W3100738191 hasRelatedWork W11016543 @default.
- W3100738191 hasRelatedWork W12544054 @default.
- W3100738191 hasRelatedWork W1802230 @default.
- W3100738191 hasRelatedWork W2882144 @default.
- W3100738191 hasRelatedWork W5281039 @default.
- W3100738191 hasRelatedWork W5574817 @default.
- W3100738191 hasRelatedWork W563404 @default.
- W3100738191 hasRelatedWork W5963666 @default.
- W3100738191 hasRelatedWork W6008397 @default.
- W3100738191 hasRelatedWork W972044 @default.
- W3100738191 isParatext "false" @default.
- W3100738191 isRetracted "false" @default.
- W3100738191 magId "3100738191" @default.
- W3100738191 workType "book-chapter" @default.