Generation of bis-Acyl Ketals from Esters and Benzyl Amines Under Oxidative Conditions
摘要:
Treatment of benzylamines with esters at an elevated temperature are expected to give amides. However, in the presence of TBAI/TBHP, esters possessing a methylene carbon alpha-to oxygen with benzylamines provide bis-esters rather than the expected amides. Benzylamines under oxidative conditions generate less nucleophilic carboxylates, which couples at the sp(3) C-H bonds of esters and cyclic ethers to give bis-acyl ketals and alpha-acyloxy ethers, respectively.