A thermal O-to-C [1,3]-rearrangement of α-hydroxy acid derived enol ethers was achieved under mild conditions. The 2-aminothiophenol protection of carboxylic acids facilitates formation of the [1,3] precursor and its thermalrearrangement via stabilization of a radical intermediate. Experimental and theoretical evidence for dissociative radical pair formation, its captodative stability via aminothiophenol
Room-Temperature Coupling/Decarboxylation Reaction of α-Oxocarboxylates with α-Bromoketones: Solvent-Controlled Regioselectivity for 1,2- and 1,3-Diketones
作者:Zhen He、Xiaotian Qi、Zhijie She、Yinsong Zhao、Shiqing Li、Junbin Tang、Ge Gao、Yu Lan、Jingsong You
DOI:10.1021/acs.joc.6b02575
日期:2017.2.3
A transition-metal-free and room-temperature coupling/decarboxylation reaction between α-oxocarboxylates and α-bromoketones is reported herein. It represents the first mild and regioselective synthesis of either 1,2- or 1,3-diketones from the same starting materials. Notably, the regioselectivity is simply controlled by solvents. The preliminary experimental data and DFT calculations suggest sequential
N-Heterocyclic carbene-catalyzed asymmetric construction of cyclopentenones using enals and α-diketones is achieved, furnishing a series of highly functionalized cyclopentenones in a highly diastereo- and enantioselective manner. The protocol tolerates substrates with both aromatic and aliphatic groups, and further transformations of the products delivered a range of value-added molecules.
2-hydroxyfuran-3(2H)-ones, 4-hydroxy-2-oxabicyclo[2.2.1]heptan-3-ones, 1,3-diaryl cyclobutanes, and 4-(furan-2(3H)-ylidene)cyclopent-2-enones. The formation of the products includes two novel rearrangement processes, and further transformations on the products can be easily achieved to deliver value-added substances such as highly functionalized cyclopentanes. Moreover, the 2-hydroxyfuran-3(2H)-one products