Total synthesis of halichondrins: Highly stereoselective construction of a homochiral pentasubstituted H-ring pyran intermediate from α-d-glucose
✍ Scribed by Seokchan Kim; Robert G. Salomon
- Publisher
- Elsevier Science
- Year
- 1989
- Tongue
- French
- Weight
- 190 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0040-4039
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✦ Synopsis
The functionality of a-D-Glucose is stereoselectively manipulated exploiting pyranose furanose ~ pyranose interconversions and lactonization for selective masking to achieve a stereocontrolled synthesis of the densely substituted H-ring pyran of halichondrins.
Halichondrins0 a family of macrolide polyethers, were isolated from a sponge, llalichondria okadai Kadota, in 4x10 -7 to 5x10-6% yields. 1 Halichondrin B (1), the biologically most active member of this new family, is a remarkably effective antitumor agent in vivo. A few doses of 10 t.tg/Kg provide T/C >200 against B-16 melanoma and T/C >300 against P-388 leukemia in mice. The 32 asymmetric carbons in 1 allow more than four billion stereoisomers.
Therefore, a practical total synthesis must be highly stereoselective.