Asymmetric Cascade Coupling-cyclization Reactions for Accessing Cyclic P-chiral Phosphorus Compounds

Asymmetric Cascade Coupling-cyclization Reactions for Accessing Cyclic P-chiral Phosphorus Compounds

Organophosphorus compounds have important applications in bioactive molecules and functionalized materials for their special properties, thus attract considerable attention from scientific community. For instance, conjugated cyclic phosphorus compounds have many favorable properties that have applications in organic electronic materials. Unlike the heterocyclic systems based on nitrogen, sulfur, or oxygen, the system based on phosphorus exhibits unique properties different from the other five/six-membered heterocyclic compounds. The substitution of the phosphine allows the tuning of the aromaticity of the conjugated systems, and a reactive phosphorus lone pair can be used to tune the physicochemical properties.

Over the years, organic electronics has extensively developed, but it remains limited by the number of conjugated backbone of oligomers and polymers that are available. In order to further expand this field, new types of cyclic P-chiral phosphorus compounds need to be designed and synthesized, especially conjugated cyclic chiral phosphorus compounds.

The classical synthetic method of chiral molecules is organic synthesis, more specifically, asymmetric synthesis. Among various asymmetric synthetic strategies, asymmetric catalysis is most effective and attractive. Transition metal-catalyzed enantioselective C-P cross-coupling reactions of secondary phosphine oxides with aryl electrophiles are attractive methods to provide convenient access to structurally diversified P-chiral phosphorus compounds. Transition metal-catalyzed intramolecular C–H cyclization provides the direct and efficient way to construct the cyclic heterocycles compounds. Riding the wave of green chemistry, catalytic cascade reactions have become one of the most active research areas in organic synthesis. Herein, we plan to devise asymmetric catalytic cascade reaction of C(sp² )–P coupling and cyclization in response to a growing demand for cyclic P‑chiral phosphorus compounds. The asymmetric cascade reactions of P−C cross-coupling/ C–H cyclization are rarely explored and remain highly challenging.

Transition-metal-catalyzed cascade reactions combine the novelty and power of asymmetric catalysis with the synthetic utility, providing a green and economically desirable approach to organic synthesis. In this proposal, the proposed the methodology of cyclic P-chiral organophosphorus products with easy accessibility will offer us an opportunity to incorporate these unique building blocks into π-extended conjugate systems and explore their application in functionalized materials which are bringing the greatest benefit to humankind.