3149-65-3Relevant academic research and scientific papers
Establishment of Guidelines for the Control of Glycosylation Reactions and Intermediates by Quantitative Assessment of Reactivity
Chang, Chun-Wei,Wu, Chia-Hui,Lin, Mei-Huei,Liao, Pin-Hsuan,Chang, Chun-Chi,Chuang, Hsiao-Han,Lin, Su-Ching,Lam, Sarah,Verma, Ved Prakash,Hsu, Chao-Ping,Wang, Cheng-Chung
supporting information, p. 16775 - 16779 (2019/11/03)
Stereocontrolled chemical glycosylation remains a major challenge despite vast efforts reported over many decades and so far still mainly relies on trial and error. Now it is shown that the relative reactivity value (RRV) of thioglycosides is an indicator for revealing stereoselectivities according to four types of acceptors. Mechanistic studies show that the reaction is dominated by two distinct intermediates: glycosyl triflates and glycosyl halides from N-halosuccinimide (NXS)/TfOH. The formation of glycosyl halide is highly correlated with the production of α-glycoside. These findings enable glycosylation reactions to be foreseen by using RRVs as an α/β-selectivity indicator and guidelines and rules to be developed for stereocontrolled glycosylation.
Visible light mediated activation and O-glycosylation of thioglycosides
Wever, Walter J.,Cinelli, Maris A.,Bowers, Albert A.
supporting information, p. 30 - 33 (2013/03/28)
Visible light catalysis allows the efficient construction of single electron transfer (SET) redox cycles that result in minimal formation of byproducts and proceed under exogenous control of a removable light source. The O-glycosylation of thioglycosides via visible light photoredox chemistry is reported. Mechanistic studies show that the reaction is fully light responsive and support a mechanism involving decomposition of an oxidatively generated sulfur radical cation and propagation via reduction of the thiol side product.
Selective cleavage of methoxy protecting groups in carbohydrates
Boto, Alicia,Hernandez, Dacil,Hernandez, Rosendo,Suarez, Ernesto
, p. 1938 - 1948 (2007/10/03)
The selective cleavage of methoxy protecting groups next to hydroxy groups is achieved using a radical hydrogen abstraction reaction as the key step. Under the reaction conditions, the hydroxy group generates an alkoxyl radical that reacts with the sterically accessible adjacent methoxy group, which is transformed into an acetal. In the second step, the acetals are hydrolyzed to give alcohols or diols. A one-pot hydrogen abstraction-hydrolysis procedure was also developed. Good yields were usually achieved, and the mild conditions of this methodology were compatible with different functional groups and sensitive substrates such as carbohydrates.
Efficient and selective removal of methoxy protecting groups in carbohydrates
Boto, Alicia,Hernandez, Dacil,Hernandez, Rosendo,Suarez, Ernesto
, p. 3785 - 3788 (2007/10/03)
(Chemical Equation Presented) The selective removal from carbohydrate substrates of methoxy protecting groups next to hydroxy groups is reported. On treatment with Phl(OAc)2-I2, the methoxy group is transformed into an easily removable acetal. The mild conditions of this methodology are compatible with many functional groups, and good to excellent yields are usually achieved.
Generation of alkoxycarbenium ion pools from thioacetals and applications to glycosylation chemistry
Suzuki, Shinkiti,Matsumoto, Kouichi,Kawamura, Kohsuke,Suga, Seiji,Yoshida, Jun-Ichi
, p. 3755 - 3758 (2007/10/03)
(Chemical Equation Presented) Alkoxycarbenium ions have been generated and accumulated as "cation pools" by the low-temperature electrochemical oxidation of α-phenylthioethers. Although an unsuccessful attempt to accumulate glycosyl cations was made, a one-pot method for electrochemical glycosylation, which involves anodic oxidation of thioglycosides to generate glycosyl cation equivalents followed by their reactions with glycosyl acceptors, has been developed.
Peralkylation of Saccharides under Aqueous Conditions
Wang, Hui,Sun, Lihong,Glazebnik, Serge,Zhao, Kang
, p. 2953 - 2956 (2007/10/02)
Treatment of saccharides with sodium hydroxide and alkyl halides in aqueous dimethyl sulfoxide solution offers a very efficient method for the complete alkylation of saccharides in high yields.
