Collect. Czech. Chem. Commun. 2006, 71, 1470-1483

Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Glucopyranoside Enantiomers

David Šamana, Pavel Kratinaa,b, Jitka Moravcováb, Martina Wimmerováa and Zdeněk Wimmera,*

a Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nám. 2, CZ-16610 Prague 6, Czech Republic
b Institute of Chemical Technology, Prague, Technická 5, CZ-16628 Prague 6, Czech Republic


Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

Keywords: Glycosides; Glycosidations; Glucosylations; Koenigs-Knorr synthesis; Enzymatic reduction; Insect juvenile hormon analogs; Juvenoids; Chiral HPLC; NMR spectroscopy.

References: 20 live references.