An Air- and Water-Stable Iodonium Salt Promoter for Facile Thioglycoside Activation
作者:An-Hsiang Adam Chu、Andrei Minciunescu、Vittorio Montanari、Krishna Kumar、Clay S. Bennett
DOI:10.1021/ol5004059
日期:2014.3.21
iodonium salt phenyl(trifluoroethyl)iodonium triflimide is shown to activatethioglycosides for glycosylation at room temperature. Both armed and disarmed thioglycosides rapidly undergo glycosylation in 68–97% yield. The reaction conditions are mild and do not require strict exclusion of air and moisture. The operational simplicity of the method should allow experimentalists with a limited synthetic background
Glycosylation Reactions Using Phenyl(trifluoroethyl)iodonium Salts
申请人:Trustees of Tufts College
公开号:US20150099870A1
公开(公告)日:2015-04-09
Provided are methods for the preparation of glycosylation products, including those represented by formula I:
Sugar-O—R′ I
comprising the step of combining R′—OH, a glycosyl sulfide glycosyl donor (“thioglycoside donor”), a hypervalent iodine alkyl-transfer activating reagent, and a base. In an embodiment, the hypervalent iodine alkyl-transfer activating reagent is (phenyl(trifluoroethyl)iodonium triflimide).
提供了制备糖基化产物的方法,包括由式I表示的那些:
糖-O—R′ I
包括将R′—OH、糖基硫醚糖基供体(“硫代糖苷供体”)、高价碘烷基转移活化试剂和碱结合的步骤。在一种实施例中,高价碘烷基转移活化试剂为(苯基(三氟乙基)碘三氟甲磺酰胺)。
Stereoselective Koenigs-Knorr Glycosylation Catalyzed by Urea
作者:Lifeng Sun、Xiaowei Wu、De-Cai Xiong、Xin-Shan Ye
DOI:10.1002/anie.201600142
日期:2016.7.4
A stereoselective Koenigs–Knorr glycosylation reaction under the catalysis of urea is described. This method is characterized by urea‐mediated hydrogen‐bond activation and subsequent glycosylation with glycosyl chlorides or bromides. Excellent yields and high anomeric selectivity can be achieved in most cases. Moreover, the low α‐stereoselectivity of glycosylations observed when using perbenzylated
(Aka) to quantify the nucleophilicity of hydroxyl groups in glycosylation influenced by the steric, electronic and structural effects, providing a connection between experiments and computer algorithms. The subtle reactivity differences among the hydroxyl groups on various carbohydrate molecules can be defined by Aka, which is easily accessible by a simple and convenient automation system to assure