Tetrabutylammonium iodide is a quaternary ammonium salt commonly used as a phase transfer catalyst, surfactant, and stabilizer in various chemical reactions, especially in transition-metal-free-catalyzed cross-coupling reactions. 

A recent studies for developingnewtransition-metal-free-catalyzedcross-coupling reactionswithTBAI/TBHPsystem. Mechanistic studies demonstrated that the roles of TBAI and TBHP: 1)TBAIas theradical initiator to decomposeTBHP to tBuO* and tBuOO* which could undergoH-abstraction fromcarboxylic acids, ethers, alde hydes, allyl CH, benzyl CH, a-Hof tertiary amines, sulfonyl hydrazides etc.; 2)TBAIas theprecursorof (hypo) iodites,whichcouldreactwithactiveXHof sulfonamides, malonate, cyanoacetic acid, nitromethane, and 2-vinylphe nols,underoxidativeenvironmentofTBHP. 

 The application of some novel trans formations developed by TBAI/TBHP in total synthesis is alsohighlyvaluable.