Bock,K. et al., Carbohydrate Research, 1979, vol. 68, p. 312 - 319
作者:Bock,K. et al.
DOI:——
日期:——
Enantiomerically pure, highly functionalized tetrahydrofurans from simple carbohydrate precursors
作者:Inge Lundt、Holger Frank
DOI:10.1016/s0040-4020(01)89337-6
日期:1994.1
6-Bromo-6-deoxy-1,4-aldonolactones and 6-bromo-6-deoxy-alditols with D-galacto-, D-altro-, D-manno- and D-ido-configuration were selectively converted into hydroxylated tetrahydrofuran derivatives by simple heating in water. The 6-bromo-6-deoxy-D-altritol (10) and 6-bromo-6-deoxy-D-iditol (25) reacted even at room temperature. Likewise, the 6-bromo-2,6-dideoxy-aldonolactones with D-arabino- (29) and D-lyxo-configuration (31) gave the corresponding 2-deoxy-3,6-anhydrides, when heated in water. The rate of formation of the furan ring by intramolecular nucleophilic substitution was determined by the conformation of the bromopolyols in water.
First synthesis of 4,5-O-isopropylidene-6-thio-d-galactono-1,6-lactone as a precursor of d-galactothioseptanose
Displacement of the bromide group in methyl 6-bromo-6-deoxy-2,3:4,5-di-O-isopropylidene-D-galactonate 7, with potassium thioacetate gave methyl 6-(S)-acetyl-2,3 :4,5-di-O-isopropylidene-6-thio-D-galactonate 8 in quantitative yield. Regioselective removal of the 2,3-ketal protecting group afforded methyl 6-(S)-acetyl-4,5-O-isopropylidene-6-thio-D-galactonate 11 in 70% yield. Saponification of compound 11 gave the 6-(S)-4,5-O-isopropylidene-6-thio-D-galactonic acid 12 in quantitative yield. Treatment of 12 with DIC/HOBt as coupling reagents gave, after cyclisation; the target compound: 4,5-O-isopropylidene 6-thio-D-galactono-1,6-lactone 13 in 49% yield. (C) 2005 Elsevier Ltd. All rights reserved.