US Patent 5,998,643
United States Patent and Trademark Office
University of Iowa Research Foundation (Iowa City, IA, US)
The process of preparing ansa-metallocene complexes in high yield by reacting a metal leaving group complex with an aluminum ansa-bis-cyclopentadienyl compound.
Jordan, Richard F.; Thiyagarajan, Bakthavachalam; and Zhang, Xingwang Metallocene synthesis. US Patent 5,998,643 filed January 15, 1999 and issued December 07, 1999. https://ir.uiowa.edu/patents/230