Radical-induced Opening of Trisubstituted Epoxides: Application in the Synthesis of C1–C12 Segment of Epothilones
✍ Scribed by T.K Chakraborty; S Dutta
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- French
- Weight
- 557 KB
- Volume
- 39
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
Disstereo-andregioselective opening ofa trisubstituted epoxy ketone atthemoresubstituted carbon using sanrarium(II) iodide presents an alternate approach to the C5-C7 afdol moiety with & hydroxyketoframework in the stereoselectivesynthesisof C1-C12 segmentof epothilones.
📜 SIMILAR VOLUMES
A Chiral synthesis ofepothilone A C7-21 segment 2 is described using epoxide opening with acetylide for the construction of the C~2.~.~ cis double bond and a modified Wittig reaction tbr introduction of the thiazole side chain.
The CI-C9 segment of epothilons was generated by an aldol reaction between chiral aldehyde 3 and ethyl ketone 4. Removal of the TBS protecting groups and debenzylation generated spiro ketal 13 which was analyzed by X-ray crystallography.
The C( 1)-C(9) segment 3 of the macrolides epothilon A and B 1, two new cytotoxic natural products, has been synthesized in a direct manner. Key steps in the synthesis are a stereoselective aldol reaction of 6 and 7 and a Brown allylation of 9.