Efficient Synthesis of an Unprecedented Enantiopure Hybrid Scorpionate/Cyclopentadienyl by Diastereoselective Nucleophilic Addition to a Fulvene

The work described here represents the first example of an enantiopure hybrid scorpionate/cyclopentadiene ligand. The ligand was obtained in a one-pot synthetic procedure by an efficient and highly diastereoselective nucleophilic addition of an organolithium reagent to an electrophilically activated olefin in a new fulvene with a chiral substrate to control the stereochemistry of a newly created asymmetric center. We verified the potential utility of this ligand as a valuable scaffold that is able to induce chirality in organometallic/coordination chemistry. This was achieved through the preparation of a new enantiomerically pure zinc complex in which the ligand behaves in a tridentate manner with a kappa(NN)-N-2-eta(1)(pi)-Cp coordination mode. This alkylzinc complex constitutes the first example of an organozinc derivative which behaves as an efficient initiator for the ROP of rac-LA in the production of isotactic-enriched poly(lactides) with P-i = 0.77.