Sequential reaction of prochiral (η6-arene)Cr(CO)3 complexes with chiral amide bases and electrophiles yielded planar chiral complexes. Benzaldehyde acetal and phenyl carbamate complexes gave o-substituted products with 64 to 81% enantiomeric excess. With the benzaldehyde acetal complex, competitive benzylic deprotonation occurred. Enantiomeric purity of the substituted carbamate complexes could be increased to > 90% ee by fractional crystallization. The racemate crystallized selectively, leaving the enantiomerically enriched complex in solution. © 1994.
Kündig, E. P., & Quattropani, A. (1994). Planar chiral arene tricarbonylchromium complexes via enantioselective deprotonation / electrophile addition reactions. Tetrahedron Letters, 35(21), 3497–3500. https://doi.org/10.1016/S0040-4039(00)73219-9