Detlef Icheln

Migration of secondary tert-butyldimethylsilyl groups in cyclomalto-heptaose and -octaose derivatives

When 2,6-di-O-tert-butyldimethylsilylated cyclomalto-oligosaccharides (cyclodextrins) are treated with allyl or methyl iodide and NaH in dry tetrahydrofuran, O-2-->O-3 migration of the secondary 2-O-tert-butyldimethylsilyl groups occurs, leading to 2-O-alk(en)yl-3,6-di-O-tert-butyldimethylsilyl-cyclodextrin derivatives. The detection and identification of the reaction step during which migration occurred is described and possible mechanisms of migration are discussed.

Gas chromatographic enantioseparation of allenes

Abstract Enantioselective gas chromatography with modified cyclodextrins as stationary phases is successfully used to separate chiral allenic hydrocarbons - including kinetically labile 1,2-cyclooctadiene - and 1-halo-1,2-butadienes.