Synthesis of Highly Functionalized Biaryls by Condensation of 2-Fluoro-1,3-bis(silyloxy) 1,3-Dienes with 3-Cyanochromones and Subsequent Domino “Retro-Michael/Aldol/Fragmentation”
摘要:
The Me3SiOTf-mediated condensation of 1-ethoxy-2-fluoro-1,3-bis(trimethylsilyloxy) 1,3-dienes with 3-cyanochromones afforded 3-cyano-2-(4-ethoxy-3-fluoro-2,4-dioxobutyl)-chroman-4-ones. Their reaction with triethylamine afforded fluorinated azaxanthones or biaryls. The product distribution depends on the structure of the diene. The formation of the biaryls can be explained by an unprecedented domino "retro-Michael/aldol/fragmentation" reaction.
Synthesis of Highly Functionalized Biaryls by Condensation of 2-Fluoro-1,3-bis(silyloxy) 1,3-Dienes with 3-Cyanochromones and Subsequent Domino “Retro-Michael/Aldol/Fragmentation”
The Me3SiOTf-mediated condensation of 1-ethoxy-2-fluoro-1,3-bis(trimethylsilyloxy) 1,3-dienes with 3-cyanochromones afforded 3-cyano-2-(4-ethoxy-3-fluoro-2,4-dioxobutyl)-chroman-4-ones. Their reaction with triethylamine afforded fluorinated azaxanthones or biaryls. The product distribution depends on the structure of the diene. The formation of the biaryls can be explained by an unprecedented domino "retro-Michael/aldol/fragmentation" reaction.
Stereoselective Reduction of α-Fluoro-β-keto Esters by NADH and NADPH-Dependent Ketoreductases
作者:Thomas K. Green、Anil Damarancha、Matthew Vanagel、Brandon Showalter、Sandra Kolberg、Alexander Thompson
DOI:10.1002/ejoc.201900644
日期:2019.7.7
Dynamicreductivekinetic resolution is applied toward the synthesis of α‐fluorinated‐β‐hydroxy esters using a set of commercially available ketoreductases. In many examples, the reactions are rapid (<1 h) and quantitative with high de and ee. 19F NMR spectroscopy proves useful for analysis of stereochemistry using in‐tube Mosher ester derivatization.
动态还原动力学拆分应用于使用一组可商购的酮还原酶合成α-氟代-β-羟基酯。在许多实例中,反应是快速的(<1小时),并且定量分析具有很高的de和ee值。19 F NMR光谱证明对使用管内Mosher酯衍生化的立体化学分析有用。