Copper-Catalyzed Oxidative Cyclization of Carboxylic Acids
作者:Shyam Sathyamoorthi、J. Du Bois
DOI:10.1021/acs.orglett.6b03176
日期:2016.12.16
for converting C–H to C–O bonds through oxidativecyclization of carboxylic acids to generate lactone products is described. The reaction employs catalytic amounts of Cu(OAc)2 and potassium persulfate as the terminal oxidant and is performed open to air in an aqueous acetic acid solvent system. Preliminary mechanistic studies suggest that substrate oxidation likely proceeds by sulfate radical anion
γ-lactonization of homopropargyl alcohols via an alkyne deprotonation/boronation/oxidation sequence has been developed. Oxidation of the generated alkynyl boronate affords the corresponding ketene intermediate, which is trapped by the adjacent hydroxy group to furnish the γ-lactone. We have optimized the conditions as well as examined the substrate scope and synthetic applications of this efficient one-pot