The stereoselective synthesis of hordenine β-L-rhamnopyranoside (3) was achieved using 4-O-acetyl-2,3-O-carbonyl-α-L-rhamnopyranosyl bromide (14) as key intermediate. The regiospecific syntheses of the peracetyl derivatives of (E)-O-(6-O-cinnamoyl-β-D-glucopyranosyl)-(1 → 2)-, (1 → 3)-, and (1 → 4)-α-L-rhamnopyranoses and of their 4-acetoxycinnamoyl counterparts were achieved through the use of various types of rhamnose-derived intermediates, i.e., 1,2-O-orthoester for the (1 → 2) series, 2,3-O-orthoester for the (1 → 3) series, and 2,3-O-isopropylidene for the (1 → 4) series.
使用4-O-乙酰基-2,3-O-羰基-α-
L-鼠李糖基
溴化物(14)作为关键中间体,实现了异构选择性合成
鼠李糖基β-L-喝荡碱苷(3)。通过使用不同类型的
鼠李糖衍生中间体,即1,2-O-正交酯用于(1→2)系列,2,3-O-正交酯用于(1→3)系列,以及2,3-O-异丙基亚甲基用于(1→4)系列,实现了(E)-O-(6-O-肉桂酰基-β-
D-葡萄糖基)-(1→2)-、(1→3)-和(1→4)-α-
L-鼠李糖苷的特定区域合成以及它们的4-乙酰氧基肉桂酰基对应物的合成。