Catalytic Allylic Chlorination of Natural Terpenic Olefins Using Supported and Nonsupported Lewis Acid Catalysts

摘要

A mild and convenient method for the allylic chlorination of naturally occurring terpenic olefins was investigated in the presence of different supported and non-supported Lewis acid catalysts.The reaction has been tested on carvone as a model substrate in the presence of sodium hypochlorite as chlorine donor.The scope and limitations of transition metal-based Lewis acid catalysts,stoichiometry,and substrate structure were evaluated.Among the iron precursors used,FeCl3 and FeCl2 provide the promise of a general approach to allylic or vinylic chlorination reaction.Various terpenic olefins were examined in the presence of FeCl3/NaOCl combination system.The catalytic chlorination proceeds under mild conditions with short reaction time and shows a high selectivity affording the corresponding chlorides in good to excellent yields.