136984-90-2Relevant articles and documents
Dehydroxy substitution reactions of the anomeric hydroxy groups in some protected sugars initiated by anodic oxidation of triphenylphosphine
Maeda, Hatsuo,Matsumoto, Sayaka,Koide, Takashi,Ohmori, Hidenobu
, p. 939 - 943 (1998)
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
Zn- And Cu-catalyzed coupling of tertiary alkyl bromides and oxalates to forge challenging C?O, C?S, and C?N bonds
Gong, Yuxin,Zhu, Zhaodong,Qian, Qun,Tong, Weiqi,Gong, Hegui
supporting information, p. 1005 - 1010 (2021/02/01)
We describe here the facile construction of sterically hindered tertiary alkyl ethers and thioethers via the Zn(OTf)2catalyzed coupling of alcohols/phenols with unactivated tertiary alkyl bromides and the Cu(OTf)2-catalyzed thiolation of unactivated tertiary alkyl oxalates with thiols. The present protocol represents one of the most effective unactivated tertiary C(sp3)? heteroatom bond-forming conditions via readily accessible Lewis acid catalysis that is surprisingly less developed.
Visible Light Enables Aerobic Iodine Catalyzed Glycosylation
Krumb, Matthias,Lucas, Tobias,Opatz, Till
, p. 4517 - 4521 (2019/08/06)
A versatile protocol for light induced catalytic activation of thioglycosides using iodine as an inexpensive and readily available photocatalyst was developed. Oxygen serves as a green and cost-efficient terminal oxidant and irradiation is performed with a common household LED-bulb. The scope of this glycosylation protocol was investigated in the synthesis of O-glycosides with yields up to 95 %.
An Empirical Understanding of the Glycosylation Reaction
Chatterjee, Sourav,Moon, Sooyeon,Hentschel, Felix,Gilmore, Kerry,Seeberger, Peter H.
supporting information, p. 11942 - 11953 (2018/09/27)
Reliable glycosylation reactions that allow for the stereo- and regioselective installation of glycosidic linkages are paramount to the chemical synthesis of glycan chains. The stereoselectivity of glycosylations is exceedingly difficult to control due to the reaction's high degree of sensitivity and its shifting, simultaneous mechanistic pathways that are controlled by variables of unknown degree of influence, dominance, or interdependency. An automated platform was devised to quickly, reproducibly, and systematically screen glycosylations and thereby address this fundamental problem. Thirteen variables were investigated in as isolated a manner as possible, to identify and quantify inherent preferences of electrophilic glycosylating agents (glycosyl donors) and nucleophiles (glycosyl acceptors). Ways to enhance, suppress, or even override these preferences using judicious environmental conditions were discovered. Glycosylations involving two specific partners can be tuned to produce either 11:1 selectivity of one stereoisomer or 9:1 of the other by merely changing the reaction conditions.
Tris(pentafluorophenyl)borane-promoted stereoselective glycosylation with glycosyl trichloroacetimidates under mild conditions
Mishra, Kunj Bihari,Singh, Adesh Kumar,Kandasamy, Jeyakumar
, p. 4204 - 4212 (2018/04/14)
Tris(pentafluorophenyl)borane-promoted stereoselective glycosylation with trichloroacetimidate glycosyl donors is described. The reactions proceed efficiently with a wide range of acceptors, from sugar to nonsugar, under mild conditions in the presence of
Silver-catalyzed stereoselective formation of glycosides using glycosyl ynenoates as donors
Dong, Xu,Chen, Li,Zheng, Zhitong,Ma, Xu,Luo, Zaigang,Zhang, Liming
, p. 8626 - 8629 (2018/08/06)
A silver-catalyzed glycosylation reaction employing readily accessible and stable glycosyl ynenoates is developed. This reaction is mostly high yielding and exhibits varying levels of stereoinversion at the anomeric position. Compared to established and versatile Yu's gold catalysis, this chemistry features the use of substantially cheaper AgNTf2.
The tertiary-butyl group: Selective protection of the anomeric centre and evaluation of its orthogonal cleavage
Subratti, Afraz,Jalsa, Nigel Kevin
, p. 2082 - 2085 (2018/05/04)
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.
1,2-trans-1-Dihydroxyboryl benzyl S-glycoside as glycosyl donor
Liu, Xiao,Zhang, Bingbing,Gu, Xiangying,Chen, Guohua,Chen, Lin,Wang, Xin,Xiong, Bing,You, Qi-Dong,Chen, Yue-Lei,Shen, Jingkang
, p. 45 - 49 (2015/01/30)
Activated by NBS, readily available 1,2-trans-1-dihydroxyboryl benzyl S-glycosides served as glycosyl donors and reacted with certain simple alcohol acceptors to produce pure 1,2-cis-O-glycosides in moderate yields. The boronic acid moiety was revealed es
Combined Lewis acid and Br?nsted acid-mediated reactivity of glycosyl trichloroacetimidate donors
Gould, Nathan D.,Liana Allen,Nam, Brandon C.,Schepartz, Alanna,Miller, Scott J.
supporting information, p. 36 - 42 (2013/11/19)
Biomimetic conditions for a synthetic glycosylation reaction, inspired by the highly conserved functionality of carbohydrate active enzymes, were explored. At the outset, we sought to generate proof of principle for this approach to developing catalytic systems for glycosylation. However, control reactions and subsequent kinetic studies showed that a stoichiometric, irreversible reaction of the catalyst and glycosyl donor was occurring, with a remarkable rate variance depending upon the structure of the carboxylic acid. It was subsequently found that a combination of Br?nsted acid (carboxylic acid) and Lewis acid (MgBr2) was unique in catalyzing the desired glycosylation reaction. Thus, it was concluded that the two acids act synergistically to catalyze the desired transformation. The role of the catalytic components was tested with a number of control reactions and based on these studies a mechanism is proposed herein.
Silicon fluorides for acid-base catalysis in glycosidations
Kumar, Amit,Geng, Yiqun,Schmidt, Richard R.
experimental part, p. 1489 - 1499 (2012/07/14)
Adduct formation between alcohols as glycosyl acceptors and phenylsilicon trifluoride (PhSiF3) as catalyst permits acid-base-atalyzed glycosidations with O-glycosyl trichloroacetimidates as glycosyl donors. In this way, from various glycosyl do
