PPh3/NaI driven photocatalytic decarboxylative cyclization of 2-isocyanobiaryls with alkyl NHP esters was developed. This simple protocol afforded a novel and environmentally friendly approach to furnish 6-alkyl phenanthridines in good yields.

Cerium photocatalytic dehydrogenative lactonization of 2-arylbenzoic acids yields synthetically useful benzo-3,4-coumarin derivatives in gram scale under mild reaction conditions.

Herein, we present a method to control the dual cross-linking of radical and urethane reactions for the enhanced polymer coatings by protecting and deprotecting vinyl functionalities using sulfoxide chemistry. We exploited this chemistry to produce highly cross-linked polymers suitable for use as protective coatings. Briefly, dually cross-linkable polymers with sulfoxide-protected vinyl and hydroxyl functionalities were synthesized. Subsequently, thermal curing resulted in the reaction of the hydroxyl functionalities with isocyanate cross-linkers to form urethane cross-links. At the same time, the sulfoxide-protected vinyl functionalities were deprotected and participated in vinyl cross-linking via radical addition reactions. The real-time monitoring of the dual-cross-linking behavior and mechanical properties of the cross-linked films revealed enhanced cross-linking when the reaction rate of the vinyl functionalities was retarded during thermal curing. Thus, this work provides insights into methods of enhancing dual-cross-linking reaction efficiency, and the developed system has applications for the low-temperature preparation of automotive clearcoats.

Polymers containing cyclic derivatives are a new class of macromolecular topologies with unique properties. Herein, we report the synthesis of a triblock copolymer containing a spirocyclic mid-block. To achieve this, a spirocyclic polystyrene (cPS) mid-block was first synthesized by atom transfer radical polymerization (ATRP) using a tetra-functional initiator, followed by end-group azidation and a copper (I)-catalyzed azide-alkyne cycloaddition reaction. The resulting functional cPS was purified using liquid chromatography techniques. Following the esterification of cPS, a macro-ATRP initiator was obtained and used to synthesize a poly (methyl methacrylate)-block-cPS-block-poly (methyl methacrylate) (PMMA-b-cPS-b-PMMA) triblock copolymer. This work provides a synthetic strategy for the preparation of a spirocyclic macroinitiator for the ATRP technique and as well as liquid chromatographic techniques for the purification of (spiro) cyclic polymers.

The reaction of alkynyl p-quinone methide (pQM) with keto-methylenes through a base-mediated tandem 1,6-addition/annulation sequence, [2 + 3] annulation, affording the furans is reported for the first time. A variety of functionalized furans, including fused derivatives, were obtained in good to excellent yields under mild reaction conditions. The efficacy of alkynyl pQMs is highlighted by extending their use to access isoxazoles, pyrazoles via [3 + 2] annulation, and pyridines through [3 + 3] annulation in the presence of different bis-nucleophiles.