Cascade Reaction to Selectively Synthesize Multifunctional Indole Derivatives by IrIII -Catalyzed C-H Activation.

An effective and condition-controlled way to synthesize with high selectivity a variety of functionalized indoles with potent biological properties has been developed. Notably, 2,4-dialkynyl indole products were obtained by direct double C-H bond alkynylation, whereas alkynyl at the C4 position could convert to carbonyl to generate 2-alkynyl-3,4-diacetyl indoles fast and effectively. Additionally, a one-pot relay catalytic reaction led to 2,5-di-alkynyl-3,4-diacetyl indoles when using a carbonyl group as the directing group and by controlling the type and quantity of additives. A possible mechanism was proposed based on many studies including deuterium-exchange experiments, the necessary conditions of product conversion, and the effect of water on the reaction.

Ruthenium-Catalyzed PIII-Directed Remote ε-C-H Alkylation of Phosphines.

The ruthenium-catalyzed remote ε-C-H alkylation of phosphines with tertiary alkyl halides has been developed. This novel PIII-directed C-H activation strategy tolerated various functional groups and delivered a wide variety of modified phosphines with excellent meta-site selectivity. Preliminary mechanistic studies indicated that a PIII-assisted ortho-cyclometalation/remote σ-activation pathway might be involved in this methodology.

Iridium(III)-Catalyzed C-H Amidation/Cyclization of NH-Sulfoximines with N-Alkoxyamides: Formation of Thiadiazine 1-Oxides.

The first example of Ir(III)-catalyzed C-H activation/cyclization with N-alkoxyamides as amidation reagents to simultaneously form functionalized thiadiazine 1-oxide derivatives was developed. This one-pot cascade protocol tolerated diverse functional groups and readily constructed various heterocyclic frameworks in moderate to good yield.

Synthesis of rhodium(iii)-catalyzed isoquinoline derivatives from allyl carbonates and benzimidates with hydrogen evolution.

A novel Rh(iii)-catalyzed cascade C-H activation/cyclization approach to access isoquinoline derivatives from benzimidates and available allyl carbonates with the liberation of H2 has been realized. Allyl carbonates were first used as a versatile and universal C2 synthon to synthesize this biological activity skeleton via an efficient and practical process just within 1 h.

Specific Synthesis of 3H-Indole Derivatives via Rh(III)-Catalyzed Cascade Annulation between N-Phenylbenzimidamides and Pyridotriazoles.

An efficient synthetic method to construct 3H-indole derivatives has been successfully developed involving rhodium-catalyzed highly selective C-H bond activation of N-phenylbenzimidamides and subsequent couplings with pyridotriazoles. This cascade approach features excellent chemoselectivity and unique of products containing quaternary carbon center with the pyridyl moiety.