Enantiofacial Discrimination in Dihapto-Coordination of Aromatic Molecules by the Chiral π-base/Lewis Acid TpRe(CO)(PMe3)

In summary, a synthetic route to the π-basic {TpRe(CO)(PMe₃)} fragment has been developed. This metal system forms stable η²-aromatic complexes with naphthalene, thiophene, and furan that approach the stability of the pentaammineosmium(II) system. While the chiral metal fragment demonstrates only modest ability to discriminate enantiofaces with the heterocycles thiophene and furan, excellent stereo-differentiation is achieved upon coordination of naphthalene. Thus, it is possible that an entirely new class of dearomatization agents may be obtained of the form {TpRe(CO)(L)} that may ultimately prove to be powerful tools for the synthetic chemist.