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An unprecedented palladium/copper cocatalyzed coupling reaction of indoles with simple aroyl hydrazides has been developed under aerobic conditions. A range of aroyl hydrazides underwent palladium/copper cocatalyzed oxidative arylation with indoles open to air in a 1:1 mixture of dimethyl sulfoxide and nitromethane to give structurally diverse 2-arylindoles or 3-arylindoles in moderate to good yields. The reaction well tolerates a wide variety of functional groups such as alkoxy, halo, ester.

An unprecedented protocol has been developed for the efficient synthesis of substituted tetrahydropyrans via a bismuth-promoted Prins cyclization of imines with homoallyl alcohols. In the presence of 40 mol% BiCl3, a wide variety of imines react smoothly with homoallyl alcohols at room temperature to give the corresponding 4-chlorotetrahydropyran derivatives in good to excellent yields.

An unprecedented deammoniative condensation reaction of primary allylic amines with nonallylic amines has been developed through CN bond cleavage. In the presence of 5 mol% palladium diacetate, 10 mol% 1,4-bis(diphenylphosphino)butane (dppb), and 5 mol% p-toluenesulfonic acid (TsOH), a range of α-unbranched primary allylic amines smoothly underwent deammoniative condensation with nonallylic amines in an α-selective fashion to give structurally diverse secondary and tertiary amines in good to excellent yields and E selectivity. Replacing dppb with racemic 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP) permitted the deammoniative condensation of enantioenriched α-chiral primary allylic amines with nonallylic amines to proceed with complete retention of configuration. Electrospray ionization (ESI) mass spectrometric analysis of the reaction mixture permitted the identification of some π-allylpalladium intermediates, and plausible mechanisms have been proposed to account for the regioselectivity and stereospecificity of the deammoniative condensation reaction.

A new cross-coupling reaction of N-benzylic sulfonamides with terminal alkynes for the synthesis of internal alkynes is reported. In the presence of 5 mol% of (Tf)2NH/Bi(OTf)3 (1:1), a broad range of N-benzylic sulfonamides react smoothly with arylacetylenes to afford structurally diverse internal alkynes in moderate to excellent yields. We reasoned that vinyl cations could be formed by the regioselective attack of terminal alkynes with benzyl cations generated in situ from N-benzylic sulfonamides under acidic conditions, which then eliminated to form a carbon-carbon triple bond.

Using Bi2(SO4)3 as the catalyst and TMSCl as the additive, a wide variety of aldehydes, ketones, and acetals were smoothly condensed with aryl ethers at room temperature to provide the corresponding diarylmethanes and triarylmethanes selectively in good to excellent yields.