Rhodium(III)‐Catalyzed Cross Coupling of Sulfoxonium Ylides and 1,3‐Diynes to Produce Naphthol‐Indole Derivatives: An Arene ortho C−H Activation/Annulation Cascade

Abstract

Synthesis of naphthol-indoles starting from easily available 1,3diynes and sulfoxonium ylides via Rh III-catalyzed CÀ H activation/ hydroamination cascade process in a one pot manner has been developed. The reaction proceeds through a Rh III-catalyzed arene ortho CÀ H activation and silver-catalyzed hydroamination cascade to afford a variety of C2 position functionalized indoles in good yields with broad substrate scope and good functional group tolerance.

α-Carbonyl sulfoxonium ylides in transition metal-catalyzed C–H activation: a safe carbene precursor and a weak directing group

“…In 2020, Shi and co-workers 86 employed 1,3-diynes 181 as coupling partners to access naphthol–indole derivatives 182 via a Rh( iii )-catalyzed C–H activation/hydroamination cascade process in a one pot manner (Scheme 84). The reaction proceeds via the Rh( iii )-catalyzed arene ortho C–H activation and silver-catalyzed hydroamination cascade to afford a variety of C2 functionalized indoles in good yields.…”

1,3‐Diynes: A Versatile Precursor in Transition‐Metal Catalyzed (Mediated) C−H Functionalizations

“…In this protocol a variety of C2 functionalized indole derivatives were achieved by using a wide range of substituted sulfoxonium ylides and 1,3-diynes under mild reaction conditions (Scheme 48). [41] A plausible mechanism for this cascade annulation is shown in Scheme 49. Very recently, Jeganmohan group described a cobalt catalyzed regioselective [4 + 2]-annulation of aromatic sulfoxonium ylides with 1,3-diynes to afford substituted 1-naphthol derivatives.…”

“…In this protocol a variety of C2 functionalized indole derivatives were achieved by using a wide range of substituted sulfoxonium ylides and 1,3‐diynes under mild reaction conditions (Scheme 48). [41] A plausible mechanism for this cascade annulation is shown in Scheme 49. The catalytic cycle initiated by generate the 2‐alkynyl indole intermediate‐ A via silver catalyzed intramolecular hydroamination of amine substituted 1,3‐diyne.…”

Rh(III)‐Catalyzed Chemodivergent Coupling of Sulfoxonium Ylides and Acryloyl Silanes

“…For example, Chatanis group reported a Rh(III)‐catalyzed reaction of sulfoxonium ylides with alkenes to afford indanone derivatives [12a] (Scheme 1a). Subsequently, Yu, [12b] Prabhu [12c] and Cheng [12d] demonstrated the use of sulfoxonium ylides as TDG to synthesize polycyclic compounds in a domino fashion, respectively (Scheme 1b, Scheme 1c, Scheme 1d), etc [12e–h] . Inspired by these elegant pioneering studies and the ubiquity of indanone cores in biologically active compounds, we envisaged the possibility of C−H activation/annulation using sulfoxonium ylides as C4 synthons to access indanone‐fused polycyclic compounds.…”