Green Synthesis of Fluorinated Arenes, Benzoxazinones and Benzamides

Abstract

Green Synthesis of Fluorinated Arenes, Benzoxazinones and Benzamides Three different types of reactions (Suzuki-Miyaura reaction, carbonylation reaction and oxidation reaction) were employed to synthesize an assortment of diverse aromatic and heterocyclic compounds. Fluorinated heterocycles are frequently found in pharmaceuticals, drug candidates, ligands for transition metal catalysts and other molecular functional materials, so efficient methods for the synthesis of these compounds are of significant value. We described a selective strategy for the synthesis of poly-substituted pyridines. The Suzuki-Miyaura reaction of 2,6-dichloro-3-(trifluoromethyl)pyridine with one equivalent of aryl boronic acids resulted in site-selective formation of 2-aryl-6-chloro- 3-(trifluoromethyl)pyridine. Due to electronic reasons, the reaction takes place at the sterically more hindered position. The reactions proceeded smoothly in the absence of phosphine ligands. A general and convenient methodology for 2-amino benzoxazinones synthesis has been developed. Radially available 2-bromoanilines and isocyanates were used as substrates and diverse products have been prepared in good yields. Notably, Mo(CO)6 as a solid CO source was applied instead of gas. x A general procedure for oxidation of both benzyl alcohols and alkyl alcohols to primary amides under catalyst free conditions has been developed. More than 25 examples of primary amides were produced from their corresponding alcohols in moderate to excellent yields. This is a practical procedure for primary amides synthesis, water and tert-butanol are the only by-products.