Metal-free synthesis of ynones via direct C–H alkynylation of aldehydes with ethynylbenziodoxolones
摘要:
A metal-free synthesis of ynones via direct allcynlyation of C-H bonds in aldehydes with ethynylbenziodoxolones is described. A variety of unactivated aldehydes undergo this transformation, affording ynones in good yields. These ynones could be further transformed into important heterocycles without purification. (C) 2015 Elsevier Ltd. All rights reserved.
A transition-metal-free synthetic method of various ynones via decarboxylative alkynylation of α-keto acids is described. The reaction is carried out undermildconditions and exhibits remarkable tolerance of functional groups. The mechanism of a radical process is proposed in the reaction.
Decarboxylative Alkynylation of α-Keto Acids and Oxamic Acids in Aqueous Media
作者:Hua Wang、Li−Na Guo、Shun Wang、Xin-Hua Duan
DOI:10.1021/acs.orglett.5b01336
日期:2015.6.19
K2S2O8 promoted decarboxylativealkynylation of α-ketoacids and oxamic acids has been developed. This process features mild reaction conditions, a broad substrate scope, and good functional-group tolerance, therefore providing a new and efficient access to a wide range of ynones and propiolamides. Furthermore, this radical process could also be successfully applied to alkynylation of the Csp2–H bond
已经开发出温和的K 2 S 2 O 8促进α-酮酸和草酰胺酸的脱羧炔基化。该工艺具有温和的反应条件,广泛的底物范围和良好的官能团耐受性,因此提供了一种新型且有效的途径,可广泛使用炔酮和丙酰胺类化合物。此外,该自由基过程也可以成功地用于高价炔碘试剂对DMF中C sp 2 -H键的炔基化反应。
Radical-Induced Metal-Free Alkynylation of Aldehydes by Direct CH Activation
A directC(sp2)H alkynylation of aldehyde C(O)H bonds with hypervalent iodine alkynylation reagents provides ynones under metal‐free conditions. In this method, 1‐[(triisopropylsilyl)ethynyl]‐1,2‐benziodoxol‐3(1H)‐one (TIPS‐EBX) constitutes an efficient alkynylation reagent for the introduction of the triple bond. The substrate scope is extended to a variety of (hetero)aromatic, aliphatic, and α
The direct acyl Sonogashira cross-coupling of carboxylic acids with terminal alkynes has been achieved through Pd/Cu cooperative catalysis. In this reaction, the readily available carboxylic acids act as the acyl source for the coupling with various terminal alkynes to produce highly valuable ynones in good to high yields. The reaction features high chemoselectivity and functional group tolerance.
The first catalytic enantioselective trifluoromethylation of alkynyl ketones 1 with (trifluoromethyl)trimethylsilane is disclosed by an operationally simple procedure, based on the combination of ammonium bromide of bis-cinchona alkaloids with Me4NF to afford trifluoromethyl-substituted tertiary propargyl alcohols (up to 96% ee), which are the important chiral building blocks for pharmaceuticals. Biologically attractive aryl heteroaryl trifluoromethyl carbinols were also synthesized.