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Synthesis of 7‐Deoxypancratistatin from Carbohydrates by the Use of Olefin Metathesis
Author(s) -
Håkansson Anders E.,
Palmelund Anders,
Holm Henriette,
Madsen Robert
Publication year - 2006
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200501429
Subject(s) - chemistry , bromide , dihydroxylation , zinc , zinc bromide , allylic rearrangement , total synthesis , pentose , yield (engineering) , olefin fiber , organic chemistry , ring closing metathesis , metathesis , combinatorial chemistry , enantioselective synthesis , catalysis , polymerization , materials science , polymer , fermentation , metallurgy
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.