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Oligosaccharide Analogues of Polysaccharides, Part 23 , Synthesis of a Dimeric Acetyleno Cyclodextrin from a Mannopyranose‐Derived Dialkyne
Author(s) -
StichlerBonaparte Jürgen,
Vasella Andrea
Publication year - 2001
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 - 10.1002/1522-2675(20010815)84:8<2355::aid-hlca2355>3.0.co;2-x
Subject(s) - chemistry , epoxide , butane , stereochemistry , ring (chemistry) , bent molecular geometry , crystal structure , cyclodextrin , crystallography , organic chemistry , catalysis
The 1,4‐ cis ‐diethynylated α ‐ D ‐mannopyranose analogue 11 has been prepared from 1,6 : 2,3‐dianhydro‐ β ‐ D ‐allopyranose ( 6 ) by alkynylating epoxide and acetal opening ( Scheme 2 ). Eglinton coupling of 11 gave the cyclodimer 18 ( Scheme 3 ). Crystal‐structure analysis of the corresponding bis(methanesulfonate) 19 revealed substantially bent butadiyne moieties; one mannopyranosyl ring adopts the 4 C 1 and the other one a slightly distorted O S 2 conformation ( Fig. 1 ). Hydrogenation of 18 , followed by deprotection, gave the stable butane‐1,4‐diyl‐bridged cyclodimer 21 ( Scheme 3 ). Crystal‐structure analysis shows the 4 C 1 conformation of the mannopyranosyl units ( Fig. 2 ). The two butane fragments are characterised by a combination of gauche and antiperiplanar arrangements.