titanocene and phosphine

Following promising recent in vitro and in vivo studies of the anticancer efficacies of heterometallic titanocene-gold chemotherapeutic candidates against renal cancer, we report here on the synthesis, characterization, stability studies and biological evaluation of a new titanocene complex containing a gold-triethylphosphane fragment [(η-C

Topics: Angiogenesis Inhibitors; Antineoplastic Agents; Cell Line, Tumor; Cell Movement; Cell Proliferation; Cell Survival; Coordination Complexes; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Humans; Kidney Neoplasms; Molecular Conformation; Neovascularization, Pathologic; Organometallic Compounds; Phosphines; Structure-Activity Relationship

The study presented herein describes a reductive transmetalation approach toward the generation of Grignard and organozinc reagents mediated by a titanocene catalyst. This method enables the metalation of functionalized substrates without loss of functional group compatibility. Allyl zinc reagents and allyl, vinyl, and alkyl Grignard reagents were generated in situ and used in the addition to carbonyl substrates to provide the corresponding carbinols in yields up to 99%. It was discovered that phosphine ligands effectively accelerate the reductive transmetalation event to enable the metalation of C-X bonds at temperatures as low as -40 °C. Performing the reactions in the presence of chiral diamines and amino alcohols led to the enantioselective allylation of aldehydes.

Topics: Aldehydes; Catalysis; Indicators and Reagents; Ligands; Organometallic Compounds; Phosphines; Stereoisomerism; Temperature; Zinc