Replacement of natural sugars by 4-deoxy-D-lyxo-hexose ("4-deoxy-D-mannose", 8) as the component parts of saccharides may endow compounds with new functions or biological activities. In previous studies, syntheses of 8 gave low overall yields or required many steps 1-4 Thus a simplified synthetic route to 8
. giving larger yields is needed.
For our purpose, levoglucosenone (1,6-anhydro-3,4-dideoxy-P-D-glycero-hex-3enopyranos-2-ulose, 1) +, which is readily available by the acidic pyrolysis of cellulose5, seemed to be an ideal starting material. We have previously reported the novel syntheses of D-altrosan (1,6-anhydro-B-D-altropyranose), D-altrose, D-allosan (1,6-anhydro-/3-D-allopyranose), D-allose, and 1,6 : 3,4-dianhydro-/3-D-talopyranose (3) from 1 as a common building block6*'.
Compound 3 is easily and stereoselectively obtained in high yield from 1 in two steps'. We tried a synthesis of 8 via the cleavage of the oxirane ring of 3 with a reductant. This method is presented in Scheme 1.
The reduction of the carbonyl group of 1 with lithium aluminum hydride stereoselectively gave 1,6-anhydro-3,4-dideoxy-8-D-threo-hex-3-enopyranose
(2) in a 70.3% yield 'p6 The trans-iodoacetoxylation of 2 with iodine and silver acetate in .
acetic acid, followed by the treatment with ammonia water in methanol, stereoselectively gave 3 in a 93.8% yield'. The reductive cleavage of the oxirane ring of 3 * Corresponding author. + Levoglucosenone (1) is available from Yuki Gosei Kogyo Co., Ltd; Hirakawa-cho CH BLDG.