Diastereoselective synthesis of planar chiral cobalt metallocene based oxazoline platinacycles

Reaction of (eta(5)-(S)-2-(4-methylethyl)oxazolinyl-cyclopentadienyl)(eta(4)-tetraph enylcyclobutadiene)cobalt with cis-bis(dimethylsulfoxide)dichloroplatinum gave a 4.7:1 ratio of diastereomeric platinacycles, and the S,R(p)-configuration of the major isomer was determined by X-ray crystallography. The same reaction on the corresponding t-Bu-substituted oxazoline derivative proceeded with a 5.6:1 selectivity, with the S,R(p)-configuration of the major isomer determined by circular dichroism. Dimethylsulfoxide- and triphenylphosphine-ligated complexes are inactive as catalysts for the allylic imidate rearrangement of a trichloroacetimidate.