Expedient Synthetic Identification of a Novel P-stereogenic Ligand Motif for the Palladium-Catalyzed Preparation of Isotactic Polar Polypropylenes.

Expedient Synthetic Identification of a Novel P-stereogenic Ligand Motif for the Palladium-Catalyzed Preparation of Isotactic Polar Polypropylenes.
Angew Chem Int Ed Engl. 2020 Sep 15;:
Authors: Seidel FW, Tomizawa I, Nozaki K
Abstract
The iso -specific statistical copolymerization of unprotected polar monomers with propylene still stands a as grand challenge in the field of polymer chemistry. Current research in the field is hampered as to date only a single natural product derived dimenthylphosphine-motif is known to allow for the preparation of moderately isotactic polypropylene copolymers. To overcome this structural limitation, we developed time-efficient synthetic protocols that minimize the tediousness associated with P-donor ligand development. The strength of these protocols was exemplified by the preparation of twenty-five new P-stereogenic Phosphine/Sulfonate and Bisphosphine Monoxide type palladium catalysts, which could typically be developed in parallel within a standard workday. This work has led to identification of a novel structural lead candidate for the iso -specific propylene polymerization. The best performing catalysts utilizing this P-stereogenic donor motif achieved triad isotacticities of up to mm = 0.75, the highest value within the reported ones with group 10 metal catalysts, for the homo- and copolymerization of propylene with unprotected polar monomers at an industrially relevant temperature of 50°C.
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Source: Angewandte Chemie - September 14, 2020 Category: Chemistry Authors: Seidel FW, Tomizawa I, Nozaki K Tags: Angew Chem Int Ed Engl Source Type: research