Rh2(esp)2: An Efficient Catalyst for O–H Insertion Reactions of Carboxylic Acids into Acceptor/Acceptor Diazo Compounds

Abstract Rh 2 (esp) 2 has been identified as a highly efficient catalyst for O–H insertion of carboxylic acids into acceptor/acceptor diazo compounds. The insertion reaction proceeds in CH 2 Cl 2 within minutes at room temperature in excellent yields and accommodates carboxylic acids having varying functionalities including amino acids, free alcoholic and phenolic O–H, indole N–H, alkenes, alkynes, and substituted aromatics. In addition, the reaction tolerates a broad range of stable diazo compounds carrying diverse functional groups.