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Carbasaccharides via Ring‐Closing Alkene Metathesis. A Synthesis of (+)‐Valienamine from D ‐Glucose
Author(s) -
Kapferer Peter,
Sarabia Francisco,
Vasella Andrea
Publication year - 1999
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/(sici)1522-2675(19990505)82:5<645::aid-hlca645>3.0.co;2-k
Subject(s) - chemistry , alkene , ring closing metathesis , cyclohexene , metathesis , diene , yield (engineering) , bromide , ring (chemistry) , salt metathesis reaction , stereoselectivity , stereochemistry , medicinal chemistry , organic chemistry , catalysis , polymer , natural rubber , materials science , metallurgy , polymerization
(+)‐Valienamine ( 16 ) was prepared in seven steps and in an overall yield of 17% from commercially available 2,3,4,6‐tetra‐ O ‐benzyl‐ D ‐glucopyranose. Stereoselective addition of vinylmagnesium bromide to the 1,3,4,5‐tetra‐ O ‐benzyl‐6,7‐dideoxy‐ L ‐ xylo ‐hept‐6‐en‐2‐ulose ( 2 ) gave diene 3 (86%). Ring‐closing alkene metathesis of 3 in the presence of 0.15 equiv. of Grubb 's catalyst 1 gave the cyclohexene 4 (58%), that was converted into (+)‐valienamine ( 16 ) in three steps and in 47% yield. Similarly, ring‐closing alkene metathesis of the D ‐mannose‐derived diene 20 gave the cyclohexene 21 (89%).