Phenyl vs. Ferrocenyl Cyclometallation Selectivity: Diastereoselective Synthesis of an Enantiopure Iridacycle

Ferrocenyl (Fc) and phenyl (Ph) containing imines FcCH=NCH(R)Ph and FcCH(R)N=CHPh (R = H and Me) were cycloiridated using [Cp*IrCl2]2 with NaOAc in CH2Cl2. All resulted in the formation of neutral chloride ligated half-sandwich iridacycles as a result of ortho-phenyl and not alpha-ferrocenyl C–H activation. The complexes derived from FcCH=NCH(R)Ph (R = H, Me) were obtained as a mixture of E and Z imine isomers, and with R = Me the product obtained from the (S)-imine was isolated by recrystallisation as a single diastereoisomer. The configuration was determined by an X-ray crystal structure analysis as SC,RIr,E