The high pressure reaction of cyclopropanes with indoles catalyzed by ytterbium triflate

Article abstract of DOI:10.1016/S0040-4039(97)01351-8

A variety of 1,1-cyclopropane dicarboxylic acid esters were reacted with a selection of indoles under hyperbarric conditions. In the presence of Yb(OTf)₃3H₂O, smooth ring opening resulted in the formation of 4-indolyl dicarboxylic acid esters. Hydrolysis and decarboxylation resulted in the formation of the mono-acids. Nucleophilic attack occurred specifically at the more hindered position of the substituted cyclopropanes.