1,6-CYCLIZATION REACTIONS OF SELECTED ALDOHEXOPYRANOSES VIA THEIR 1-O-TOSYL DERIVATIVES

2,3,4,6-Tetra-O-acetyl-D-gluco-, D-galacto- and D-mannopyranoses were tosylated with p-tolenesulfonyl chloride to afford their 1-O-tosyl der ivatives which were cyclized ''in situ'' in a methanolic solution of s odium methoxide. 1,6-Cyclization products were obtained only with D-gl ucose and D-galactose derivatives. Cyclization of derivatives of D-glu cose i.e. 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosy chloride, 4,6-tr i-Owacetyl-1,2-anhydro-alpha-D-glucopyranose (Brigl's anhydride) and 2 ,3,4,6-tetra-O-acetyl-alpha-D-glucopyranosyl bromide enabled the estim ation of the influence of configuration at C-l and C-2 on the course o f cyclization. All product mixtures were separated by capillary gas ch romatography (CGC) and their components were identified by coinjection with standards.