Synthesis of 7-deoxypancratistatin from carbohydrates by the use of olefin metathesis.
The stereocontrolled synthesis of (+)-7-deoxypancratistatin is described. The convergent synthesis has been achieved by two different strategies, both of which commence from a pentose and piperonal. The latter is converted into allylic bromide 7, which is then coupled with a protected methyl 5-deoxy-5-iodo-D-ribofuranoside in the presence of zinc metal. The first strategy involves a total of only 13 steps from D-ribose and piperonal, but suffers from a low yield in the zinc-mediated reaction between ribofuranoside 9, benzylamine, and bromide 7. The second strategy involves a total of 18 steps from D-xylose and piperonal. The former is converted into ribofuranoside 28, which is coupled with bromide 7 in the presence of zinc, and this is followed by ring-closing olefin metathesis. Subsequent Overman rearrangement, dihydroxylation, and deprotection then affords the natural product.
Håkansson
Anders E
AE
Center for Sustainable and Green Chemistry, Department of Chemistry, Building 201, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
Palmelund
Anders
A
Holm
Henriette
H
Madsen
Robert
R
D000475:Alkenes / Q000737:chemistry*; D047151:Amaryllidaceae Alkaloids / Q000138:chemical synthesis* / Q000737:chemistry; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry; D002241:Carbohydrates / Q000737:chemistry*; D007546:Isoquinolines / Q000138:chemical synthesis* / Q000737:chemistry
C418326:7-deoxypancratistatin; D000475:Alkenes; D047151:Amaryllidaceae Alkaloids; D000970:Antineoplastic Agents; D002241:Carbohydrates; D007546:Isoquinolines