Synthesis of 5-O-methyl-d-galactofuranose

M. SZNAIDMAN; A. FERNÁNDEZ CIRELLI; R. MUCHNIK DE LEDERKREMER

CARBOHYDRATE RESEARCH

Elsevier

Lugar: Amsterdam; Año: 1986 vol. 146 p. 233 - 240

0008-6215

5-O-Methyl-d-galactofuranose (7) was synthesized, for the first time, in five steps from d-galactono-1,4-lactone (1) in good overall yield. Tritylation and further acetylation of 1 gave 2,3,5-tri-O-acetyl-6-O-trityl-d-galactono-1,4-lactone (2); prolonged acetylation caused elimination to form 2,5-di-O-acetyl-3-deoxy-6-O-trityl-d-threo-hex-2-enono-1,4-lactone. Detritylation of 2 with BF3 · Et2O occurred with acetyl migration and afforded 2,3,6-tri-O-acetyl-d-galactono-1,4-lactone (4). Methylation of 4 with CH2N2---BF3 · Et2O gave 5-O-methyl-2,3,6-tri-O-acetyl-d-galactono-1,4-lactone. Subsequent reduction by disiamylborane followed by controlled deacetylation gave crystalline 7. The 1H- and 13C-n.m.r. spectra of 7 indicated a 1:1.3 ratio of the á and â furanose anomers.