Iron‐Catalyzed Tertiary Alkylation of Terminal Alkynes with 1,3‐Diesters via a Functionalized Alkyl Radical
作者:Ming‐Qing Tian、Zhen‐Yao Shen、Xuefei Zhao、Patrick J. Walsh、Xu‐Hong Hu
DOI:10.1002/anie.202100641
日期:2021.4.19
Direct oxidative C(sp)−H/C(sp3)−H cross‐coupling offers an ideal and environmentally benign protocol for C(sp)−C(sp3) bond formations. As such, reactivity and site‐selectivity with respect to C(sp3)−H bond cleavage have remained a persistent challenge. Herein is reported a simple method for iron‐catalyzed/silver‐mediated tertiary alkylation of terminal alkynes with readily available and versatile 1
An improved procedure for the synthesis of labelled fatty acids utilizing diethyl malonate
作者:Takhar Kasumov、Henri Brunengraber
DOI:10.1002/jlcr.1034
日期:2006.2
An improved procedure for the preparation and purification of labeledfattyacids by malonic ester synthesis has been developed. This method uses the different hydrolysis rates of the monoalkylmalonic ester intermediate and its dialkylmalonic ester side product. A convenient GC–MS monitoring technique allows performing this 3-step procedure without isolation of intermediates and gives a good yield
with different MIPA isotopomers in D2O and H2O unambiguously indicated that the 5′‐deoxyadenosyl (dAdo)‐radical‐mediated hydrogen abstraction is from the amino group of l‐tryptophan and not a protein residue. Surprisingly, the dAdo‐radical‐mediated hydrogen abstraction occurs at two different sites of MIPA, thereby partitioning the substrate into different reaction pathways. Together with identification
Phosphane-Catalyzed [3+2] Annulation of Allenoates with Aldehydes: A Simple and Efficient Synthesis of 2-Alkylidenetetrahydrofurans
作者:Silong Xu、Lili Zhou、Renqin Ma、Haibin Song、Zhengjie He
DOI:10.1002/chem.200901276
日期:2009.9.7
Ylide is the key: The phosphane‐catalyzed [3+2] annulation of 2 a with aromatic aldehydes 1 to form tetrahydrofurans 3 in moderate to excellent yields is described (see scheme). This reaction represents an efficient and convergent one‐step route toward the construction of tetrahydrofurans and demonstrates a distinctive reactivity pattern of γ‐substituted allenoates with aldehydes.