Formation of unexpected substitution patterns in sulfonylbutylation of cyclomaltoheptaose promoted by host-guest interaction.
The distribution of substituents in sulfonylbutylethers of cyclomaltoheptaose (beta-cyclodextrin) formed in aqueous medium has been determined by gas chromatography after hydrolysis and formation of the permethylated sulfonylfluoride derivatives. In contrast to other etherification reactions of beta-cyclodextrin, preferred substitution in position 3 of the glucose units has been detected. From 1H NMR and microcalorimetric experiments, the formation of host-guest complexes by beta-cyclodextrin and the reagent 1,4-butane sultone in water became evident. This spatial preorganization presumably favors the reaction with the O-3. In contrast, in methyl sulfoxide preferred 2-O-alkylation was obtained, indicating that host-guest interaction does not influence regioselectivity in this solvent.
Rogmann
N
N
Universität Hamburg, Institut für Organische Chemie, Germany.
Seidel
J
J
Mischnick
P
P
D000476:Alkanesulfonates / Q000737:chemistry*; D002151:Calorimetry; D002849:Chromatography, Gas; D003505:Cyclodextrins / Q000737:chemistry*; D004987:Ethers / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D047392:beta-Cyclodextrins
D000476:Alkanesulfonates; D003505:Cyclodextrins; D004987:Ethers; D047392:beta-Cyclodextrins; C000335:butanesultone; C031215:betadex