375392-55-5Relevant academic research and scientific papers
Induction of planar chirality in formation of (η5:η1-1-(1-cyclohexyl-2-(diphenylphosphino)ethyl) indenyl)-carbonylrhodium and (η5:η1-1-(2-phenyl-2-(diphenylphosphino)ethyl)inde nyl)carbonylrhodium
Brookings, Daniel C.,Harrison, Stephen A.,Whitby, Richard J.,Crombie, Barry,Jones, Ray V.H.
, p. 4574 - 4583 (2008/10/08)
The enantiopure bidentate indenyl-phosphine ligands (1S)-[2-(3H-inden-1-yl)-1-phenyl-ethyl]diphenylphosphine (9) and [(2R)-2-cyclohexyl-2-(3H-inden-1-yl)ethyl]diphenylphosphine (18) were synthesized in 20% yield and three steps from (R)-styrene oxide and in 61% yield and four steps from vinylcyclohexane, respectively. In both cases ring opening of a spirocyclopropane-1,1′-indene with potassium diphenylphosphide was a key step. Addition of the lithium salts of 9 and 18 to [Rh(μ-Cl)(CO)2]2 gave (η5:η1-indenyl-CH2CH(Ph)PPh2 )RhCO and (η5:η1-indenyl-CH(Cy)CH2PPh2 )RhCO as 75:25 and 78:22 mixtures of diastereoisomers, from which the major complexes were readily obtained by crystallization. The chiral centers in the linking chain β and α to the indenyl ring had thus induced good planar chirality of the complexed indenyl moiety. Both complexes were characterized by X-ray crystallography.
