Synthesis and x-ray structure of metalated rhodium(II) catalysts with a chiral phospholane

The reaction of Rh-2(O2CR)(4) (R = CH3, CF3) with the chiral phosphane (2S,5S)-2,5-dimethyl-1-phcnylphospholane (PC* H), results in the formation of two diastereoisomers of Rh-2(O2CCR)(2)(PC*)(2), with (P) and (M) configuration. These can easily be isolated by chromatographic methods to obtain enantiomerically pure Rh-II compounds. Preliminary catalytic studies have shown that they induce moderate asymmetry in the cyclization of 5-aryl-1-diazo-2-pentanones and 1-diazo-5-hexen-2-one. X-ray analysis of the (M) diastereoisomer with formula Rh-2(O2CCCH3)(2)(PC*)(2) is reported. The crystallographic parameters are as follows: space group P2(1)2(1)2 (orthorhombic) with a = 12.1347(11) Angstrom, b = 14.5870(13) Angstrom, c = 9.8171(9) Angstrom.