Nucleosides. Part LXIII. Acetals as new 2?-O-protecting functions for the synthesis of oligoribonucleotides: Synthesis of uridine building blocks and evaluation of their relative acid stability
A broad variety of new acyclic vinyl ethers (see 6–41) have been synthesized via the vinyl-interchange reaction of ethyl vinyl ether at room temperature using mercury(II) trifluoroacetate as a highly efficient catalyst. The appropriate vinyl ethers were reacted under acidic conditions with 3′,5′-O-silyl-protected uridine 42 to the corresponding 2′-O-(1-alkoxyethyl) derivatives 43–83 which gave, on
Vinylethers can be protonated to generate oxocarbenium ions that react with Me3SiCN to form cyanohydrin alkylethers. Reactions that form racemic products proceed efficiently upon conversion of the vinylether to an α-chloro ether prior to cyanide addition in a pathway that proceeds through Brønsted acid-mediated chloride ionization. Enantiomerically enriched products can be accessed by directly protonating
乙烯基醚可以质子化以生成氧代碳正离子,该离子与 Me 3 SiCN反应形成氰醇烷基醚。在通过布朗斯台德酸介导的氯离子电离进行的途径中,在加入氰化物之前将乙烯基醚转化为 α-氯醚后,形成外消旋产物的反应有效进行。可以通过用手性布朗斯台德酸直接质子化乙烯基醚以形成手性离子对来获得对映体富集的产品。Me 3 SiCN 作为亲核试剂,PhOH 在不对称双分子亲核加成到氧碳鎓离子的罕见例子中作为化学计量质子源。计算研究为催化剂和氧代碳正离子之间的相互作用提供了模型。
Novel Compound, Photosensitive Resin Composition Comprising the Same, and Color Filter
申请人:Samsung SDI Co., Ltd.
公开号:US20170107224A1
公开(公告)日:2017-04-20
A compound represented by Chemical Formula 1 wherein each substituent is the same as defined in the specification, a photosensitive resin composition including the same, and a color filter manufactured using the photosensitive resin composition are provided.
Chiral phosphoramidite–olefin hybrid ligands were found to be effective in the iridium-catalyzed asymmetric alkylation of N-arylbenzamides with vinyl ethers. The reaction is catalyzed by a hydroxoiridium catalyst coordinated with the hybrid ligand to give the corresponding products in high yields with high branch selectivity and enantioselectivity.
A novel and convenient palladium catalytic system for the synthesis of α‐amino acid esters from simple starting materials is reported. Hydrogenperoxide not only acts as the green oxidant, but also as the oxygen source. This strategy for the conversion of amines and vinyl ethers into highly functionalized and structurally diverse α‐amino acid esters is characterized by the simplicity of the experimental