Diastereo‐ and Enantioselective Synthesis of Organometallic Bis(helicene)s by a Combination of CH Activation and Dynamic Isomerization

Homochiral and heterochiral cis ‐bis‐cycloplatinated‐[6]helicene derivatives 1 b 1, 2 , as representative examples of platina[6]helicenes that share a common platinum center, have been prepared. A diastereo‐ and enantioselective synthesis, which combines CH activation and dynamic isomerization from heterochiral structure 1 b 2 into homochiral structure 1 b 1 , is also described. Overall, this isomerization process results in the transfer of chiral information from one helicene moiety to the other one. The chiroptical properties of homochiral ( P )‐ and ( M )‐ 1 b 1 were greatly modified upon oxidation into their corresponding ( P )‐ and ( M )‐diiodo‐Pt IV complexes ( 5 ). The changes were also analyzed by performing theoretical calculations. CH activation in the synthesis of organometallic helicenes is further demonstrated by the preparation of cis ‐bis‐cycloplatinated‐[8]helicene 1 c .