Catalytic σ-Bond Annulation with Ambiphilic Organohalides Enabled by β-X Elimination

Abstract

We describe a catalytic cascade sequence involving directed C(sp3)–H activation followed by β-heteroatom elimination to generate a PdII(π-alkene) intermediate that then undergoes redox-neutral annulation with an ambiphilic aryl halide to access 5- and 6-membered (hetero)cycles. Various alkyl C(sp3)–oxygen, nitrogen, and sulfur bonds can be selectively activated, and the annulation proceeds with high diastereoselectivity. The method enables modification of amino acids with good retention of enantiomeric excess, as well as σ-bond ring-opening/ring-closing transfiguration with low-strain heterocycles. Despite its mechanistic complexity, the method employs simple conditions and is operationally straightforward to perform.