Premium
First Preparation of Spacer‐Linked Cyclic Neooligoaminodeoxysaccharides
Author(s) -
Chen Guangwu,
Kirschning Andreas
Publication year - 2002
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 - 10.1002/1521-3765(20020617)8:12<2717::aid-chem2717>3.0.co;2-p
Subject(s) - metathesis , chemistry , ring closing metathesis , stereochemistry , dimer , glycosidic bond , double bond , lewis acids and bases , salt metathesis reaction , ring (chemistry) , anomer , catalysis , combinatorial chemistry , organic chemistry , polymerization , enzyme , polymer
The preparation of novel cyclic 1,4‐butanediol‐linked oligoaminodeoxysugars 3 – 5 and 7 is described which are potential binders to polynucleotides. Neooligosaccharides 3 – 5 are assembled by two consecutive metathesis protocols. In the first phase metathesis‐mediated dimerization of an aminodeoxymonosaccharide which was either allylated at the anomeric center or at C4 led to E / Z mixtures of C 2 ‐symmetric homodimers which were transformed into the corresponding 1,4‐butanediol linked disaccharides by catalytic hydrogenation of the central olefinic double bond. Double O‐allylation of the head‐to‐head dimer set the stage for macrocyclization by means of ring‐closing metathesis. This ring‐closing process was highly dependent of the configuration in the carbohydrate moieties. arabino ‐Configured homodimer 15 directly yielded the macrocycle 32 which contains two sugar units while under the same metathesis conditions the corresponding ribo ‐configured starting homodimer 19 afforded cyclic neotetra‐ and neohexasaccharides 34 and 35 after a preceding dimerization and trimerization step, respectively. In addition, homodimer 23 was coupled with silylglycoside 14 a under Lewis‐acid promoted glycosidation conditions to furnish the doubly glycosylated homodimer 31 . Ring‐closing metathesis afforded the macrocyclic neoaminodeoxyoligosaccharide 36 with alternating 1,4‐butanediol linkage and glycosidic bond. The primary cyclization products were finally transformed into the respective cyclic neoaminodeoxyoligosaccharides 3 – 5 and 7 by catalytic hydrogenation and standard deprotection conditions.