Reactions of organoplatinum complexes with dimethylamine-borane

The reactions of dimethylamine-borane with platinum(ii) or platinum(iv) triflate complexes gave, not the anticipated sigma-complexes, but the respective hydridoplatinum complexes. The reaction with [Pt(OTf)Me-3(NN)], with NN = 2,2 '-bipyridine (bipy) and 4,4 '-di-t-butyl-2,2 '-bipyridine (bu(2)bipy), gave the rare stable bridging hydridoplatinum(iv) complexes [mu-H{PtMe3(NN)}(2)][OTf] and the reaction with [Pt(O2CCF3)Me(NN)] gave the unstable hydridoplatinum(ii) complex [PtHMe(NN)]. The unstable hydridoplatinum(ii) complexes could be trapped by reaction with methyl acrylate by forming the insertion products [PtCl(CHMeCO2Me)(bipy)] and [Pt(CHMeCO2Me)(2)(bipy)]. The complex [PtCl(CHMeCO2Me)(bipy)] reacted with methyl iodide to give [PtClIMe(CHMeCO2Me)(bipy)], by cis oxidative addition, and the presence of two chiral centers in the product platinum(iv) complex allowed a detailed stereochemical pathway to be proposed.

Automated summary

The reactions of dimethylamine-borane with platinum(ii) or platinum(iv) triflate complexes resulted in hydridoplatinum complexes instead of the expected sigma-complexes. The reaction with [Pt(OTf)Me-3(NN)] yielded stable bridging hydridoplatinum(iv) complexes, while reaction with [Pt(O2CCF3)Me(NN)] produced unstable hydridoplatinum(ii) complexes. The unstable hydridoplatinum(ii) complexes could be trapped by reaction with methyl acrylate to form insertion products.