Regiodivergent Synthesis of Methylene and Methyl Ring-Fused Isoquinolinones: Base-Promoted Isomerization of N-Allyl Amides

Nucleophilic Addition of Amides to Haloalkynes: Synthesis of (Z)-β-Halovinyl Amides as Dual Precursors of Alkylidene Carbenes and Allyl Halides

Toward a regioselective method for the synthesis of β-halovinyl amides, we developed a transition-metal-free nucleophilic addition reaction of amides to haloalkynes. The regioselective nucleophilic addition was achieved under solvent-free conditions using phosphonates to protonate the intermediate alkylidene carbenoids, thus suppressing their decomposition. Furthermore, we demonstrate that β-halovinyl amides can serve as dual precursors of allyl halides and alkylidene carbenes to obtain functionalized indoles and pyrrolidones.

A Neutral PCNHCP Co(I)-Me Pincer Complex as a Catalyst for N-Allylic Isomerization with a Broad Substrate Scope

Earth-abundant-metal catalyzed double bond transposition offers a sustainable and atom-economical route toward the synthesis of internal alkenes. With an emphasis specifically on internal olefins and ethers, the isomerization of allylic amines has been particularly under represented in the literature. Herein, we report an efficient methodology for the selective isomerization of N-allylic organic compounds, including amines, amides, and imines. The reaction is catalyzed by a neutral PCNHCP cobalt(I) pincer complex and proceeds via a π-allyl mechanism. The isomerization occurs readily at 80-90 °C, and it is compatible with a wide variety of functional groups. The in situ formed enamines could additionally be used for a one-pot inverse-electron-demand Diels-Alder reaction to furnish a series of diversely substituted heterobiaryls, which is further discussed in this report.