The first synthesis of highly strained spirocyclobutane-pyrrolines via a palladium-catalyzed tandem Narasaka−Heck/ C(sp 3 or sp 2 )−H activation reaction is reported here. The key step in this transformation is the activation of a δ-C−H bond via an in situ generated σ-alkyl-Pd(II) species to form a five-membered spiropalladacycle intermediate. The concerted metalation-deprotonation (CMD) process, rate-determining step, and energy barrier of the entire reaction were explored by density functional theory (DFT) calculations. Moreover, a series of control experiments was conducted to probe the rate-determining step and reversibility of the C(sp 3 )−H activation step.

Herein, a highly regioselective propargylic benzylation with propargylic carbonates and benzyl 1,4-dihydropyridines derivatives was developed via photoredox/ palladium dual-catalyzed process, which represent a novel catalytic model for non-terminal propargylic functionalization....

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A novel palladium-catalyzed spirocyclization through sequential Narasaka-Heck, C-H activation and [4+2] annulation has been developed. In this reaction, cheap and readily available 2-chlorobenzoic acid or ethyl phenylpropiolate was employed as...