Synthesis of Hydroxamic Acids by Using the Acid Labile O-2-Methylprenyl Protecting Group
作者:Aigars Jirgensons、Anna Nikitjuka
DOI:10.1055/s-0032-1317687
日期:——
Coupling of carboxylicacids with O-2-methylprenyl hydroxylamine provided O-protected hydroxamic acids, which could be deprotected by treatment with trifluoroacetic acid (TFA) in dichloromethane giving volatile by-products. Protected hydroxamic acids could be N-arylated or alkylated followed by deprotection to give N-substituted hydroxamic acids.
Cp*Co(III)-catalyzed C H amidation of azines with dioxazolones
作者:Yanzhen Huang、Chao Pi、Zhen Tang、Yangjie Wu、Xiuling Cui
DOI:10.1016/j.cclet.2020.08.046
日期:2020.12
Abstract Cp*Co(III)-catalyzed direct C H amidation of azines has been developed. This conversion could proceed smoothly in the absence of external oxidants, acids or bases, with excellent regioselectivity and broad functional group tolerance. CO2 was released as the sole byproduct, thus providing an environmentally benign amidation process. The products obtained are important intermediates in organic
Thioether-Directed NiH-Catalyzed Remote γ-C(sp<sup>3</sup>)–H Hydroamidation of Alkenes by 1,4,2-Dioxazol-5-ones
作者:Bingnan Du、Yuxin Ouyang、Qishu Chen、Wing-Yiu Yu
DOI:10.1021/jacs.1c05834
日期:2021.9.22
amidation of unactivated alkenes. Due to the preference for five-membered nickelacycle formation, the chain-walking isomerization initiated by the NiH insertion to an alkene can be terminated at the γ-methylene site remote from the alkene moiety. By employing 2,9-dibutyl-1,10-phenanthroline (L4) as the ligand and dioxazolones as the reagent, the amidation occurs at the γ-C(sp3)–H bonds to afford the amide
A base-mediated self-propagative Lossen rearrangement of hydroxamic acids for the efficient and facile synthesis of aromatic and aliphatic primary amines
aromatic and aliphatic hydroxamic acids were converted to the corresponding primary amines via base-mediated rearrangement. This rearrangement could proceed with less than 1 equiv. of K2CO3 in polar solvents under thermal conditions with no external reagents. This rearrangement has several features including no external activating agents needed for promoting the rearrangement, less than one equivalent of
通过碱介导的重排将多种芳族和脂族异羟肟酸转化为相应的伯胺。这种重新排列可以少于1个当量进行。无需外部试剂的热条件下,在极性溶剂中分离K 2 CO 3。该重排具有几个特征,包括不需要用于促进重排的外部活化剂,少于一当量的碱足以进行该反应,以及其中仅产生二氧化碳作为副产物的清洁反应。提出了通过异氰酸酯中间体的自增长机理,并通过实验支持了基本的反应步骤,即链增长反应。
P(III)‐Assisted Electrochemical Access to Ureas via in situ Generation of Isocyanates from Hydroxamic Acids
作者:Haiwen Meng、Kunhui Sun、Zhimin Xu、Lifang Tian、Yahui Wang
DOI:10.1002/ejoc.202100113
日期:2021.3.19
P(III)‐assisted electrochemical generation of isocyanates from hydroxamic acids was successfully applied in the synthesis of ureas. Hydroxamic acids were directly used without pre‐activation, and the reaction was found not sensitive to water or air. The process started with the anodic oxidation of hydroxamic acids, followed by reacting with trivalent phosphine to form corresponding alkoxyphosphoniums