- The tertiary-butyl group: Selective protection of the anomeric centre and evaluation of its orthogonal cleavage
-
The tertiary-butyl group has not been examined extensively as a protecting group. In this work, we describe the synthesis of tert-butyl glycosides via the Fischer glycosylation protocol. Furthermore, its utility as a temporary anomeric protecting group was evaluated. A range of differentially protected monosaccharides was used to investigate the stability of the tert-butyl group upon the introduction of other protecting groups; and compatibility of its cleavage in the presence of the latter.
- Subratti, Afraz,Jalsa, Nigel Kevin
-
supporting information
p. 2082 - 2085
(2018/05/04)
-
- Direct glycosylation of bioactive small molecules with glycosyl iodide and strained olefin as acid scavenger
-
A new strategy for diversity-oriented direct glycosylation of bioactive small molecules was developed. This reaction features (-)-β-pinene as acid scavenger and work with glycosyl iodides under mild conditions. With the aid of RP-HPLC and chiral SFC separation techniques, the new direct glycosylation proved effective at gram scale on bioactive small molecules including AZD6244, podophyllotoxin, paclitaxel, and docetaxel. Interesting glycoside derivatives were efficiently created with good yields and 1,2-cis selectivity.
- Gu, Xiangying,Chen, Lin,Wang, Xin,Liu, Xiao,You, Qidong,Xi, Wenwei,Gao, Li,Chen, Guohua,Chen, Yue-Lei,Xiong, Bing,Shen, Jingkang
-
p. 1100 - 1110
(2014/03/21)
-
- NaBH3CN and other systems as substitutes of tin and silicon hydrides in the light or heat-initiated reduction of halosugars: A tunable access to either 2-deoxy sugars or 1,5-anhydro-itols
-
UV light-promoted reduction of acetobromoglucose by NaBH3CN in t-BuOH afforded 1,3,4,6-tetra-O-acetyl-2-deoxy-α-d-arabino-hexopyranose in high yield and purity, via a Surzur-Tanner rearrangement, while, with 10 mol % thiophenol added, acetylated 1,5-anhydro-d-glucitol was cleanly obtained. Such tin-free and mild reductions, presumed to proceed via radical pathways, were more efficient with NaBH3CN compared to NaBH4 or NaBD 4, and do not occur with acetochloroglucose. Similar reductions to 1,3,4,6-tetra-O-acetyl-2-deoxy-α-d-arabino-hexopyranose were achieved upon heating to 80 C t-BuOH or CH3CN solutions of NaBH3CN and AIBN, but with a lower selectivity due to competing ionic reactions. With other pyranosyl bromides, reductions by NaBH3CN could be tuned similarly (d-galacto), but some (d-manno, 5-thio-d-xylo) gave mainly or exclusively 1,5-anhydro-itols. Other conditions, or reagents promoting SET process, afforded also reduced products, but with lower rates or selectivities. Primary iodides were reduced readily with NaBH3CN under UV light.
- Bruyère, Isabelle,Tóth, Zoltan,Benyahia, Hamida,Xue, Jia Lu,Praly, Jean-Pierre
-
supporting information
p. 9656 - 9662
(2013/10/22)
-
- InCl3.3H2O: An efficient Lewis acid catalyst for stereoselective O-glycosidation reactions of per-O-acetylglycopyranosyl trichloroacetimidates
-
InCl3.3H2O catalysed highly stereoselective O-glycosidation of per-O-acetylglycopyranosyl trichloroacetimidates with a variety of aliphatic alcohols in dichloromethane at room temperature furnishes the corresponding glycosides in very good yields with excellent 1,2-trans stereoselectivity.
- Ghosh, Rina,Chakraborty, Arijit,Maiti, Dilip Kumar
-
p. 602 - 604
(2007/10/03)
-
- Dehydroxy substitution reactions of the anomeric hydroxy groups in some protected sugars initiated by anodic oxidation of triphenylphosphine
-
The anodic transformation of 2,3:5,6-di-O-isopropylidene-α-D- mannofuranose (4) and 2,3,4,6-tetra-O-benzyl-D-glucopyranose (5) to the corresponding alkoxy phosphonium ions induces dehydroxy substitution of the sugars at the anomeric positions. Their dehyd
- Maeda, Hatsuo,Matsumoto, Sayaka,Koide, Takashi,Ohmori, Hidenobu
-
p. 939 - 943
(2007/10/03)
-
- Relations entre la reactivite d'une molecule immobilisee et son support
-
Functionalized polymers, may be used as well for organic synthesis as for chromatographic packings.According to the preparation procedure various textures of the support may be obtained.The network structure plays always a role on the reactivity of the supported species.Some examples are given to illustrate the influence of the steric hindrance due to the macromolecular network, the change in micropolarity and the rate of functionalization.
- Audebert, Roland,Quivoron, Claude
-
p. 1107 - 1114
(2007/10/02)
-