Cobalt-catalyzed annulation of styrenes with α-bromoacetic acids
作者:Tung T. Nguyen、Bao H. T. Ngo、Huy X. Le、Linh N. P. Vu、Tuong A. To、Anh N. Q. Phan、Nam T. S. Phan
DOI:10.1039/d0ra09588e
日期:——
We report a method for addition of α-bromophenylacetic acids to vinyl CC bonds in styrenes to afford γ-lactones. Reactions employed a simple cobalt catalyst Co(NO3)2·6H2O in the presence of dipivaloylmethane (dpm) ligand. Many functionalities including halogen, ester, and nitro groups were compatible with reaction conditions. If α-bromoesters were used, vinylacetates were the major products.
我们报告了一种将 α-溴苯乙酸添加到苯乙烯中的乙烯基 C C 键以提供 γ-内酯的方法。在二戊酰甲烷 (dpm) 配体存在下,反应使用简单的钴催化剂 Co(NO 3 ) 2 ·6H 2 O。许多官能团,包括卤素、酯和硝基,都与反应条件相容。如果使用 α-溴代酯,醋酸乙烯酯是主要产品。
Regioselective Synthesis of γ-Lactones by Iron-Catalyzed Radical Annulation of Alkenes with α-Halocarboxylic Acids and Their Derivatives
An abundant and low toxicity iron catalyst has enabled regioselective annulation of alkenes with α-halocarboxylic acids and their derivatives. The reaction proceeds smoothly without any additional ligands, bases, and additives to afford a variety of γ-lactones in good yields. A proposed reaction pathway through radical annulation is supported by some mechanistic studies, involving radical clock and
Carbon-Centered Radical Addition to OC of Amides or Esters as a Route to CO Bond Formations
作者:Dong Liu、Shan Tang、Hong Yi、Chao Liu、Xiaotian Qi、Yu Lan、Aiwen Lei
DOI:10.1002/chem.201404607
日期:2014.11.17
typical applied unsaturated substrates include alkenes, alkynes and imines. Carbonyl is perhaps the most common unsaturated group in nature. This work demonstrates a novel CO bond formation through carbon‐centered radical addition to the carbonyloxygen of amide or ester, in which amide and ester groups are easily activated through the radical process. EPR spectroscopy and radical clock experiments
Catalytic Redox Chain Ring Opening of Lactones with Quinones To Synthesize Quinone-Containing Carboxylic Acids
作者:Xiao-Long Xu、Zhi Li
DOI:10.1021/acs.orglett.9b01672
日期:2019.7.5
Catalytic ringopening of five- to eight-membered lactones with quinones is achieved through a redox chain mechanism. With low loading of a simple metal triflate Lewis acid catalyst and a chain initiator, C–H bonds of many quinones were efficiently functionalized with carboxylic acid-containing side chains. This method also features 100% atom economy and wide substrate scope. A novel route to the anti-asthma
Visible-Light-Induced C–O Bond Formation for the Construction of Five- and Six-Membered Cyclic Ethers and Lactones
作者:Honggu Im、Dahye Kang、Soyeon Choi、Sanghoon Shin、Sungwoo Hong
DOI:10.1021/acs.orglett.8b03166
日期:2018.12.7
Visible-light-induced intramolecular C–O bond formation was developed using 2,4,6-triphenylpyrylium tetrafluoroborate (TPT), which allows the regiocontrolled construction of cyclic ethers and lactones. The reaction is likely to proceed through the single-electron oxidation of the phenyl group, followed by the formation of a benzylic radical, thus preventing a competing 1,5-hydrogen abstraction pathway