Kang Hyun Jung
Download
1 / 21

Kang Hyun Jung - PowerPoint PPT Presentation


  • 118 Views
  • Uploaded on

Kang Hyun Jung. Introduction. Leucascandrolide A ( 1 , Scheme 1) was isolated in 1996 from the calcareous sponge Leucascandra caveolata , collected off the east coast of New Caledonia, by Pietra and co-workers.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Kang Hyun Jung' - candra


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

Introduction

Leucascandrolide A (1, Scheme 1) was isolated in 1996 from the calcareous sponge Leucascandra caveolata,

collected off the east coast of New Caledonia, by Pietra and co-workers.

- This polyoxygenated 18-membered macrolide features two trisubstituted tetrahydropyran rings, one of

which has an unusual oxazole-bearing unsaturated side chain.

- Biological studies revealed potent cytotoxic activity against a range of cancer cell lines (IC50¼0.05 and

0.25 mgmL1 against KB oral epidermoid carcinoma and P388 leukemia cell lines, respectively), as well

as pronounced antifungal activity.





HgII-Mediated Hydration of Alkyne [2]

- Alkynes are less basic than alkenes, Hg(OAc)2 (Hg+2 is a Lewis acid) is added to ensure complete reaction



1,3-Anti Reduction of β-Hydroxy Ketone[4]

J. Am. Chem. Soc., 110, 11, 3560-3578, 1988


Selective Iodine(III)/TEMPO-Mediated Oxidation [5]

J. Org. Chem., 62, 6974-6977, 1997



DIBAL Reduction and in situ Acetylation [6]

J. Org. Chem., 61, 8317-8320, 1996





α-Alkylation of Hydrazone and Alkyl halide [9]





Conclusion

  • In summary, we have completed a highly stereocontrolled synthesis

  • of the potent cytotoxic macrolide leucascandrolide A, proceeding in

  • 23 steps from 8 (longest linear sequence) and 5.3% overall yield. Key

  • features include a Jacobsen asymmetric hetero Diels-Alder reaction

  • to configure the right-hand tetrahydropyran ring, a 1,5-anti aldol

  • coupling, control over the C17 hydroxy center, and two sequential

  • Mitsunobu reactions, to close the 18-membered macrolactone and

  • append the oxazole-bearing side chain, respectively.


ad