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Palladium-catalyzed cycloaromatization of N-acyl-2-aminobiaryls, through a sequence of ortho C−H bond activation/alkyne insertion/meta C−H bond activation/alkyne insertion, was developed. An efficient synthesis of multiaryl-substituted naphthalenes, N-[2-(5,6,7,8-tetraarylnaphthalen-1-yl)aryl]acetamides, was demonstrated using molecular oxygen as the sole oxidant. Furthermore, through Buchwald's synthetic protocol, two compounds were converted into corresponding fluorescent carbazoles in 30–40% yield by intramolecular C−N bond formation.

A highly regioselective synthesis of pyrido[2,1-a]isoindolium salts from 2-arylpyridines and two equivalents of electron-deficient alkenes catalyzed by rhodium is demonstrated. The reaction was carried out in aqueous medium at 110 °C using inexpensive oxygen as oxidant. Reverse aza-Michael addition of the isoindolium salt occurs when the salt was treated with base to give a β-disubstituted alkene product. A reaction mechanism involving an ortho C–H olefination of 2-arylpyridine by alkene, intramolecular aza-Michael addition, deprotonation at the β-carbon of the alkene fragment followed by another Michael addition to give the final product is proposed.

An efficient o-arylation of pivalamides by aryl iodides via rhodium(III)-catalyzed C–H activation is demonstrated for the first time. Further, the biaryl products can be converted effectively into biologically active phenanthridine and phenanthridinone derivative.

A regioselective synthesis of indoles from arylhydrazine hydrochlorides with alkynes and diethyl ketone catalyzed by a rhodium complex is described. A possible mechanism involving an in-situ generated oxidizing directing group NNCR1R2 assisted ortho-CH activation and reductive elimination are proposed. The catalytic reaction is highly compatible with a wide range of functional arylhydrazines and alkynes. The reaction proceeds under mild reaction conditions and is atom-step economical.

A nickel-catalyzed regio- and stereoselective reductive coupling of oxa- and azabicyclic alkenes with activated alkenes and electron-rich alkynes is described. Thus, 7-oxabenzonorbornadienes underwent reductive coupling with various vinyl ketones such as ethyl, methyl, propyl and alpha-methyl-substituted vinyl ketones, in the presence of a nickel(II) iodide (NiI2), zinc (Zn), and water catalyst system in acetonitrile at 50 degrees C for 14 h to afford 2-alkylnaphthalenes in good to excellent yields. Under similar reaction conditions, 7-azabenzonorbornadiene derivatives provided cis-2-alkyl-1,2-dihydro-naphthalene derivatives in high yields. On the other hand, the nickel(II) iodide, tris(4-fluorophenyl)phoshine [P(4-FC6H4)(3)] and zinc catalyst system successfully catalyzed the reductive coupling reaction of electron-rich alkynes, with 7-aza- and 7-oxabenzonorbornadienes to give cis-2-alkenyl-1,2-dihydronaphthalene derivatives in good to excellent yields. In the reaction, a mild reducing agent (zinc) and simple hydrogen source (water) were used.

Moreover, the intramolecular reductive coupling of ene-phthalimide (XI) proceeds highly diastereoselective.

The reductive coupling of an aryl carbonyl group with an activated alkene to give the corresponding γ-hydroxybutyric acid (GHBA) derivative was achieved in the presence of zinc and ammonia. A board scope of GHBA derivatives could be synthesized under ambient conditions by this method. A mechanism involving a Zn-ketyl radical as the key intermediate is proposed.

A simple efficient method for the iron(III)-catalyzed synthesis of substituted β-chlorovinyl ketones and α,β-alkynyl ketones from terminal and silyl-substituted alkynes with acid chlorides, respectively, is described. This method features easily available starting materials, a cheap and non-toxic catalyst, simple manipulation and mild reaction conditions. Evidence shows that the catalytic addition of the acid chloride to a terminal alkyne to give (Z)-β-chlorovinyl ketones favours a concerted pathway via a four-membered ring transition state between the two alkyne carbons and the carbon-chloride bond of the acid chloride.

A new catalytic system for β-alkylation of lactic acid with primary alcohols has been developed. In the presence of nickel(II) acetate tetrahydrate [Ni(OAc)2(H2O)4] and base, lactic acid reacts with primary alcohols to afford the corresponding coupled α-hydroxy carboxylic acids in good to excellent yields via a hydrogen transfer process without any hydrogen acceptor or hydrogen donor.