Multi-component reactions assemble complex molecules in a highly effective way, however they often suffer from long reaction times. We demonstrate that acceleration of a five-component spiro-pyrrolidine construction can be achieved...

Viscosity modifying agents are one of the most critical components of hydraulic fracturing fluids, ensuring the efficient transport and deposition of proppant into fissures.

13C kinetic isotope effects (KIEs) for the photoredox-promoted [2 + 2] cycloaddition of enones were determined in homocoupling and heterocoupling examples. The only significant KIEs were observed at the β carbon, indicating that Cβ–Cβ bond formation is irreversible. However, these KIEs were much lower than computational predictions, suggesting that product selectivity is determined in part by a step prior to Cβ–Cβ bond formation. The results are explained as arising from a competition between C–C bond formation and electron exchange between substrate alkenes. This idea is supported by a relatively small substituent effect on substrate selectivity. The possible rates for electron transfer and bond-forming steps are analyzed, and the competition appears plausible, particularly if the mechanism involves a complex between reduced and neutral enone molecules.

Large intramolecular 13C kinetic isotope effects (KIEs) for the di-π-methane rearrangement of benzobarrelene fit with statistical expectations from heavy-atom tunneling when a low-energy sensitizer is employed, but much lower KIEs are observed with higher-energy sensitizers. These results in combination with trajectory studies suggest that the excess vibrational energy available from triplet energy transfer leads to hot and nonstatistical dynamics in the rearrangement.

The synthesis of water-soluble (η6-arene)ruthenium(II) complexes based on pyrazolyl–naphthyridine ligands modified with a carboxylate group is reported. The complexes are easily accessible in good yields via complexation of [(arene)RuCl2]2 with 7-pyrazolyl-1,8-naphthyridine-2-carboxylic acid (1). All complexes have been characterized by spectroscopic and elemental analyses. The complexes {[Ru(η6-arene)( N,N ′-1)Cl]Cl} (arene = benzene (5), p-cymene (6)) were further confirmed by X-ray diffraction studies. These complexes are soluble in water (ca. 10 mg/mL) and are catalytically active in hydrogen-transfer reduction of carbonyl compounds in aqueous medium with the use of HCOOH/HCOONa as the hydrogen source.