Construction of Metal-Centered Chirality:  Diastereoselective Addition of the Meerwein Reagent (Me₃OBF₄) to Rhodium Carbonyl Complexes Having the Cp‘-P Ligand

Reaction of the rhodium(I) carbonyl complexes [η⁵:η¹-{3-(R)Ind-P}_n=2]Rh(CO) (1; R = H (a), Et (b), Cy (c), (1‘S,2‘S,5‘R)-neomenthyl (NM) (d), (1‘R,2‘R,5‘R)-neoisomenthyl (NIM) (e)) with the Meerwein reagent (Me₃OBF₄) afforded the cationic rhodium(III) complexes [[η⁵:η¹-{3-(R)Ind-P}_n=2]RhMe(CO)]BF₄, having metal-centered chirality, in good to excellent yields. When a bulkier substituent (R) was used, the corresponding cationic complex was obtained with higher diastereoselectivity. In the case of using an optically active substituent such as NM or NIM, complete stereodiscrimination around the rhodium center by the Meerwein reagent occurred to give the cationic complexes with 100% de.