Induction of planar chirality in formation of (eta(5):eta(1)-1-(1-cyclohexyl-2-(diphenylphosphino)ethyl)indenyl)-carbonylrhodium and (eta(5):eta(1)-1-(2-phenyl-2-(diphenylphosphino)ethyl)indenyl)carbonylrhodium

The enantiopure bidentate indenyl-phosphine ligands (1S)-[2-(3H-inden-1-yl) -1-phenylethyl] diphenylphosphine (9) and [(2R)-2-cyclohexyl-2-(3H-inden-1- yl)ethyl]diphenylphosphine (18) were synthesized in 20% yield and three ste ps from (R)-styrene oxide and in 61% yield and four steps from vinylcyclohe xane, respectively. In both cases ring opening of a spirocyclopropane-1,1'- indene with potassium diphenylphosphide was a key step. Addition of the lit hium salts of 9 and 18 to [Rh(mu -Cl)(CO)(2)](2) gave (eta (5):eta (1)-inde nyl-CH2CH(Ph)PPh2)RhCO and (eta (5):eta (1)-indenyl-CH(Cy)CH2PPh2)RhCO as 7 5:25 and 78:22 mixtures of diastereoisomers, from which the major complexes were readily obtained by crystallization. The chiral centers in the linkin g chain beta and alpha to the indenyl ring had thus induced good planar chi rality of the complexed indenyl moiety. Both complexes were characterized b y X-ray crystallography.