Regioselective synthesis of unsymmetrical C-aryl glycosides using silicon tethers as disposable linkers.
Silicon tethers were employed to control the regiochemistry of Diels-Alder reactions between substituted benzynes and glycosyl furans as a key step in the syntheses of unsymmetrical representatives of three major groups of C-aryl glycosides. The cycloaddition precursors were readily prepared by O-alkylation of substituted phenols with various sugar-substituted furylsilane derivatives. Selective deprotonation on the benzene ring of these ethers led to a benzyne that underwent an intramolecular Diels-Alder reaction to give bridged cycloadducts. Fluoride-induced removal of the silicon tether and acid-catalyzed ring opening of the oxabicycloheptadiene subunit yielded the desired C-aryl glycosides as single isomers.
Kaelin
David E
DE
Department of Chemistry and Biochemistry, University of Texas, Austin, TX 78712-0615, USA.
Sparks
Steven M
SM
Plake
Hilary R
HR
Martin
Stephen F
SF
D001555:Benzene Derivatives / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry; D005663:Furans / Q000737:chemistry; D006027:Glycosides / Q000138:chemical synthesis / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*
D001555:Benzene Derivatives; D003432:Cross-Linking Reagents; D005663:Furans; D006027:Glycosides; D012825:Silicon