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Synthesis of Trisaccharides by Hetero‐Diels–Alder Welding of Two Monosaccharide Units
Author(s) -
Himanen Jatta A.,
Pihko Petri M.
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200277
Subject(s) - chemistry , trisaccharide , monosaccharide , stereoselectivity , glycosidic bond , catalysis , organic chemistry , diene , stereochemistry , enzyme , natural rubber
A new strategy for the synthesis of di‐ and trisaccharides based on the de novo synthesis of the linking saccharide unit is presented. In this strategy, functionalized monosaccharide building blocks already incorporating the glycosidic linkages are welded together using a metal‐catalyzed hetero‐Diels–Alder (HDA) reaction to generate a new monosaccharide unit between them. The highest yields and selectivities in the HDA reaction were obtained by using chiral Schiff base chromium complexes. Disaccharide products were accessible by reaction of Danishefsky's diene with acetyl‐ and benzyl‐protected galactoside aldehydes. For the synthesis of trisaccharide products, acetyl‐protected glucose or galactose‐derived dienes were fused with monosaccharide‐derived aldehydes using chromium catalysts for the HDA reaction. The desired trisaccharide products were obtained in moderate to good yields with excellent stereoselectivity. The central pyranulose‐ring generated in the process possessed an L ‐ cis ‐enulose configuration according to NMR spectroscopy and modeling studies.