Alkyne Hydroheteroarylation: Enantioselective Coupling of Indoles and Alkynes via Rh-Hydride Catalysis

Abstract

We report an enantioselective coupling between alkynes and indoles. A Rh-hydride catalyst isomerizes alkynes to generate a metal-allyl species that can be trapped with both aromatic and heteroaromatic nucleophiles.

CuH-Catalyzed Enantioselective Alkylation of Indole Derivatives with Ligand-Controlled Regiodivergence

“…In these transformations, the indole derivatives generally serve as the nucleophilic coupling fragments, reacting with a variety of electrophiles, including activated olefins, ketones, imines, allylic alcohol derivatives, and alkynes. [3][4][5] Most alkylation reactions take place largely or entirely at C3, due to the higher nucleophilicity at this position (Figure 1b). 6,7 The development of methods that generate enantioenriched N-alkylated indoles has been an active area of research for the past few years.…”

Access to 3‐Oxindoles from Allylic Alcohols and Indoles

“…[10] In these transformations, the use of unsymmetrical allylic substrates raises control of the regioselectivity,a nd severalr uthenium precatalysts have shown excellent activities for the formation of branched products. [11] Interestingly,m ethodst owards the introduction of an allylic or an alkyl fragment were developed by using transition-metal-catalyzeda llylic substitution or borrowing hydrogen methodology and more recently by hydroelementation starting from simple allylic or aliphatic alcohols [12][13][14][15][16][17] and alkyneso ra llenes; [18] these methods provide au seful atom-economical toolbox to access allylated and alkylated in- doles. Recently,s ome of us reported the synthesis of an allylation ruthenium precatalyst by designing ana llylic ruthenium(IV) complex featuring ap hosphine-sulfonate chelate, and its efficiency in regio-and chemoselective allylation from various allylic alcohols was proven.…”

Catalytic vinylogous cross-coupling reactions of rhenium vinylcarbenoids

“…The transformation is complementary to Pd-, Ir-, Rh-based protocols that make use of other types of allyl precursors. 25 – 28 Moreover, instances of completely unsubstituted vinylcarbene complexes, as exemplified by 6 , are quite unusual as only a handful of examples, even of other metals, have been previously reported. 16 , 17 , 24 , 29 – 34 …”