Two tunable cascade reactions of alkynols and alkynes have been developed by combining Sc(OTf)₃ and rhodium catalysis. In the absence of H₂O, an endo-cycloisomerization/CH activation cascade reaction provided 2,3-dihydronaphtho[1,2-b]furans in good to high yields. In the presence of H₂O, the product of alkynol hydration underwent an addition/CH activation cascade reaction with an alkyne, which led to the formation of 4,5-dihydro-3H-spiro[furan-2,1′-isochromene] derivatives in good yields under mild reaction conditions. Mechanistic studies of the cascade reactions indicated that the rate-determining step involves CH bond cleavage and that the hydration of the alkynol plays a key role in switching between the two reaction pathways.

Two tunable cascade reactions of alkynols and alkynes have been developed by combining Sc(OTf)₃ and rhodium catalysis. In the absence of H₂O, an endo-cycloisomerization/CH activation cascade reaction provided 2,3-dihydronaphtho[1,2-b]furans in good to high yields. In the presence of H₂O, the product of alkynol hydration underwent an addition/CH activation cascade reaction with an alkyne, which led to the formation of 4,5-dihydro-3H-spiro[furan-2,1′-isochromene] derivatives in good yields under mild reaction conditions. Mechanistic studies of the cascade reactions indicated that the rate-determining step involves CH bond cleavage and that the hydration of the alkynol plays a key role in switching between the two reaction pathways.

Cross-coupling is of great importance in organic synthesis. Here it is demonstrated that cross-coupling of aryl-bromide and porphyrin-bromide takes place on a Au(111) surface in vacuo. The products are oligomers consisting of porphyrin moieties linked by p-phenylene at porphyrin’s meso-positions. The ratio of the cross-coupled versus homocoupled bonds can be regulated by the reactant concentrations. Kinetic Monte Carlo simulations were applied to determine the activation barrier. It is expected that this reaction can be employed in other aryl-bromide precursors for designing alternating co-polymers incorporating porphyrin and other functional moieties.

The ruthenium-catalyzed alkenylation of arenes with alkynes or alkenes has been achieved by using 1,2,3-triazole as the directing group for the C–H activation. With [Ru(p-cymene)Cl₂]₂ as the catalyst and Cu(OAc)₂·H₂O and AgSbF₆ as additives, various triazole-substituted arenes reacted readily with a range of internal alkynes or terminal alkenes to afford di- or monoalkenylated arenes with high regioselectivity and in moderate-to-excellent yields.

On-surface Pd- and Cu-catalyzed CC coupling reactions between phenyl bromide functionalized porphyrin derivatives on an Au(111) surface have been investigated under ultra-high vacuum conditions by using scanning tunneling microscopy and kinetic Monte Carlo simulations. We monitored the isothermal reaction kinetics by allowing the reaction to proceed at different temperatures. We discovered that the reactions catalyzed by Pd or Cu can be described as a two-phase process that involves an initial activation followed by CC bond formation. However, the distinctive reaction kinetics and the CC bond-formation yield associated with the two catalysts account for the different reaction mechanisms: the initial activation phase is the rate-limiting step for the Cu-catalyzed reaction at all temperatures tested, whereas the later phase of CC formation is the rate-limiting step for the Pd-catalyzed reaction at high temperature. Analysis of rate constants of the Pd-catalyzed reactions allowed us to determine its activation energy as (0.41±0.03) eV.

A dicationic dichloro-bipyridine-ruthenium complex shows very high catalytic activity in redox isomerization of allylic alcohols but a relatively low one in transfer hydrogenation of ketones; surprisingly, the analogous dimethyl-bipyridine-ruthenium complex shows reverse catalytic activities in the two reactions.

The microwave-assisted substitution of β-dicarbonyl compounds with secondary alcohols has been achieved efficiently, using very cheap fluoroboric acid (HBF₄) as the catalyst. For various β-dicarbonyl compounds and a series of secondary alcohols, the direct substitution gives high yields after only 5 min of microwave irradiation.