Stereoselective de novo synthesis of (5R)-3,4:5,6-di-O-isopropylidene-d-ribo-hexos-5-ulo-5,2-furanose
摘要:
A concise and stereoselective de novo synthesis of the protected oxidized sugar (5R)-3,4:5,6-di-O-iso-propylidene-D-ribo-hexos-5-ulo-5,2-furanose is described. The synthetic sequence involves a stereoselective proline-catalyzed aldol reaction of an orthogonally protected L-glyceraldehyde derivative and 2,2-dimethyl-1,3-dioxan-5-one, to obtain 5-0-acetyl-6-0-benzy1-1,3-isopropylidene-L-psicose as a key intermediate, and the final product in 5 steps and 38% yield. (C) 2016 Elsevier Ltd. All rights reserved.
L-nucleosides are conformationally constrained by at least one additional ring formed by a bridge connecting at least two atoms within a sugar moiety of the nucleoside. While a single additional ring is formed by bridging C
1
-C
4
atoms, two additional rings are formed by bridging both C
1
-C
2
, and C
3
-C
4
atoms, or C
1
-C
3
and C
2
-C
4
atoms by bridges having the general structure A—B—Z. The conformationally constrained nucleosides may be incorporated into oligonucleotides and dinucleotides, and it is contemplated that compositions including the conformationally constrained nucleosides may have superior viral inhibitory or antineoplastic properties.
L 型核苷在构象上受到至少一个附加环的限制,该附加环由连接核苷糖分子内至少两个原子的桥形成。虽然单个附加环是由 C
1
-C
4
原子桥接形成一个附加环,而两个附加环则是通过桥接两个 C
1
-C
2
和 C
3
-C
4
原子,或 C
1
-C
3
和 C
2
-C
4
原子通过具有一般结构 A-B-Z 的桥相连。构象受约束的核苷可掺入寡核苷酸和二核苷酸中,包括构象受约束的核苷的组合物可能具有优异的病毒抑制或抗肿瘤特性。