Thornbury Richard T, Saini Vaneet, Fernandes Talita de A, Santiago Celine B, Talbot Eric P A, Sigman Matthew S, McKenna Jeffrey M, Toste F Dean
Department of Chemistry , University of California , Berkeley , California 94720 , USA . Email:
Novartis Institutes for Biomedical Research , Cambridge , Massachusetts 02139 , USA.
Chem Sci. 2017 Apr 1;8(4):2890-2897. doi: 10.1039/c6sc05102b. Epub 2017 Feb 9.
A mild palladium-catalyzed ligand-controlled regioselective 1,3-arylfluorination of 2[]-chromenes has been developed. The products with a -1,3 substitution pattern were obtained with high enantiomeric excess using a PyrOx ligand, wherein the utility of these pyranyl-fluorides was further demonstrated through their participation in a diastereoselective C-C bond forming reaction. Ligand dependent divergent formation of both the 1,3- and 1,2- alkene difunctionalization products was observed. The nature of this bifurcation was investigated through experimental studies in combination with computational and statistical analysis tools. Ultimately, the site selectivity was found to rely on ligand denticity and metal electrophilicity, the electronics of the boronic acid, and the donor ability of the directing group in the substrate.
已开发出一种温和的钯催化配体控制的2[]-色烯的区域选择性1,3-芳基氟化反应。使用PyrOx配体以高对映体过量获得具有-1,3取代模式的产物，其中这些吡喃基氟化物通过参与非对映选择性C-C键形成反应进一步证明了其效用。观察到配体依赖性地形成1,3-和1,2-烯烃双官能化产物。通过结合计算和统计分析工具的实验研究来研究这种分歧的本质。最终发现位点选择性取决于配体的齿合度和金属亲电性、硼酸的电子性质以及底物中导向基团的给体能力。
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