Ketenimines as Intermediates To Access Difluoromethoxylated Scaffolds
作者:Anaïs Loison、Gilles Hanquet、Fabien Toulgoat、Thierry Billard、Armen Panossian、Frédéric R. Leroux
DOI:10.1021/acs.orglett.2c03283
日期:2022.11.18
We report herein the in situ generation of difluoromethoxylated ketenimines. This novel intermediate is readily obtained from the corresponding oxime through a Beckmann rearrangement. The reactivity potential of this species is demonstrated as it easily undergoes addition of various nucleophiles, with a great modularity of the starting oxime. The broad applicability of this transformation leads to
Nickel-Catalyzed Reductive Allylation of Aldehydes with Allylic Alcohols in the Presence of CO<sub>2</sub>
作者:Zeyu Zhang、Jiayuan Li、Chanjuan Xi
DOI:10.1021/acs.orglett.3c03528
日期:2023.11.17
CO2-assisted and Ni-catalyzed direct reductive allylation of aldehydes utilizing allylicalcohols as allylic precursor has been reported. Various homoallyl alcohols could be synthesized in excellent yield with enhanced regioselectivity and stereoselectivity for alkyl- and aryl-substituted aldehydes under mild conditions. For different substrates, proper collocation of the catalytic precursor and ligand
Synthesis of Fluoromethyl‐Substituted Cyclopropanes by Electrophilic Cyclization of Homoallylic Boronate Intermediates
作者:Natsuki Oyama、Hajime Ito
DOI:10.1002/adsc.202300529
日期:2023.10.13
The electrophiliccyclization via the boronate complex between various homoallylic boronates and Selectfluor® is reported. This reaction provides a fluoromethylated cyclopropane ring that was difficult to synthesize by previous methods. The use of phenyl lithium, which activates the homoallylic boronate, is important for the reaction. The intermediate boronate species in this reaction was observed
据报道,各种同烯丙基硼酸酯和 Selectflu® 之间通过硼酸酯络合物进行亲电环化。该反应提供了以前的方法难以合成的氟甲基化环丙烷环。苯基锂的使用对反应很重要,它可以活化高烯丙基硼酸酯。通过11 B 1 H} NMR 实验观察到该反应中的中间体硼酸盐物质。我们还演示了构建模块的合成,包括用于生物活性化合物的氟甲基取代的环丙烷。
Switchable divergent di- or tricarboxylation of allylic alcohols with CO2
Visible-light-driven switchable divergent di- or tricarboxylation of allylic alcohols with CO is realized to selectively upgrade multiple CO units to polycarboxylic acids. The derivatization of corresponding polycarboxylic acids could deliver the potential functional materials in luminescence and biomaterials.
An enantioselective synthesis of chiral alkylphosphonates bearing a beta-stereogenic center, based on the Rh-catalyzed asymmetric hydrogenation of corresponding beta-substituted beta,gamma-unsaturated phosphonates with a Ferrocene-based monophosphoramidite ligand Under the mild hydrogenation conditions, was developed, in which an ee value of up to 98% was obtained.