Catalytic and Chemoselective Oxidation of Activated Alcohols and Direct Conversion of Diols to Lactones with In Situ-Generated Bis-IBX Catalyst

The twisted 3,3-diiodo-2,2,6,6-tetramethoxybiphenyl-4,4-dicarboxylic acid (DIDA) was designed and synthesized for the in situ generation of Bis-IBX and catalytic oxidations. The seemingly better solubility of the in situ-generated Bis-IBX and the attenuated reactivity arising from its unique structural features and methoxy substituents allowed the catalytic oxidation of activated alcohols selectively using DIDA/oxone. Chemoselective oxidations were demonstrated for substrates containing two different hydroxy groups. Furthermore, the unique reactivity of DIDA was demonstrated for sequential oxidation reactions of 1,4- and 1,6-diols to give lactones catalytically in respectable yields.