Dicationic platinum(II) complexes bearing the tridentate ligand PPP catalyze the cyclization of 1,6- and 1,7-dienes to provide bicyclo [3.1.0] and [4.1.0] compounds.  To overcome the difficulty of modifying the PPP ligand, we have deconstructed it into a modular set of diphosphine and monophosphines (P₂P), which enable more efficient screening of chiral mono- and diphosphines. 

The active dicationic catalyst, (P₂)(P)Pt²⁺, was accessible through  Ag⁺  activation   of  the  corresponding  (P₂)PtI₂  complexes  in  the  presence  of  monophosphine  (Eq. 1).   We will report that the yield and diastereoselectivity of the product cyclopropanes are sensitive to the bite angle of the diphosphine and the cone angle and basicity of the monophosphine.  When chiral diphosphines are utilized, the products are obtained in enantiomerically enriched form (>80% ee).  Details of reaction optimization and scope will also be reported.