Room-Temperature Pd-Catalyzed Synthesis of 1-(Hetero)aryl Selenoglycosides
作者:Mingxiang Zhu、Mouad Alami、Samir Messaoudi
DOI:10.1021/acs.orglett.0c02352
日期:2020.8.21
A general protocol for functionalization of an anomeric selonate anion at roomtemperature has been reported. By using the PdG3 XantPhos catalyst, the cross-coupling between the in situ-generated glycosyl selenolate and a broad range of (hetero)aryl and alkenyl iodides furnished a series of functionalized selenoglycosides in excellent yields with perfect control of the anomeric configuration.
We described a novel palladium-catalyzed domino procedure for the preparation of (hetero)aryl thio/selenoglycosides. Readily available (hetero)aryl iodides and easily accessible 1-thiosugars/1-selenosugars are utilized as the substrates. Meanwhile, 10 types of sugars are quite compatible with this reaction with good regio- and stereoselectivity, high efficiency, and broad applicability (up to 89%,
alkyl and aryl selenoglycosides, selenoglycosyl amino acid and selenodisaccharide have been synthesized in a stereoselective manner. The key precursor of α-anomeric selenolate anion was designed as p-methylbenzoyl selenoglycoside, which was synthesized by the reaction of β-glycosyl chloride with potassium p-methylselenobenzoate. Upon the action of piperazine or methylhydrazine in the presence of Cs2CO3
已经以立体选择的方式合成了多种α-硒代糖苷,包括烷基和芳基硒代糖苷,硒代糖基氨基酸和亚硒二糖。α异头selenolate阴离子的关键前体被设计为p -methylbenzoyl selenoglycoside,其通过β-糖基氯与钾反应,合成p -methylselenobenzoate。在Cs 2 CO 3的存在下,哌嗪或甲基肼的作用下,酰基硒代糖苷产生异头型硒酸根阴离子,其与各种亲电子部分原位反应生成α-硒代糖苷。
A Facile Method for β-Selenoglycoside Synthesis Using β-<i>p</i>-Methylbenzoyl Selenoglycoside as the Selenating Unit
The reaction between alpha-glycosyl bromides and potassium p-methylselenobenzoate yields beta-p-methylbenzoyl selenoglycosides. The acyl selenoglycosides were activated by the action of a secondary amine and CS2CO3 to produce an anomeric selenolate anion, which reacted in situ with various electrophiles to yield novel selenoglycosides while retaining the anomeric stereochemistry.