Net Intermolecular Silyloxypyrone-Based (5+2) Cycloadditions Utilizing Amides as Enabling and Cleavable Tethers.

Silyloxypyrone-based (5+2) cycloadditions were facilitated by amides that allowed for increased reactivity and a pathway for cleaving the tether to afford net intermolecular cycloadducts. Various amides underwent facile cycloaddition, and several experiments revealed steric and electronic factors that accelerate the reaction. -Butyl amides reacted faster than less hindered variants in multiple cases.

Large-Scale Sonochemical Synthesis of Bi-Sn Eutectic Alloy Nanoparticles.

Lead-free Bi-Sn alloy is an alternative solder material with a low eutectic melting temperature and environmental compatibility. Although extensive research has been conducted on this Bi-Sn eutectic alloy, a lack of facile synthetic methods with scalability hinders the implementation of finepatterned interconnectors for emerging electronic applications. In this study, we employed a facile sonochemical synthetic method to synthesize Bi-Sn alloy nanoparticles in large quantities.

Trapping of 1,2-cyclohexadiene: A DFT mechanistic study on the reaction of 1,2-cyclohexadiene with olefins and nitrones.

The mechanistic aspects of cycloaddition reactions of 1,2-cyclohexadiene with olefins and nitrones have been investigated with DFT calculations. The results show that the cycloaddition reactions of 1,2-cyclohexadiene with olefins do not go through a concerted pathway (one-step mechanism) but rather a stepwise one involving the formation of a biradical intermediate which then closes to form final cycloadduct. Electron-withdrawing substituents on the 1,2-cyclohexadiene decrease the activation barrier of the biradical-forming step but increase the barrier of the product-forming step and product stability, while electron-donating substituents on the 1,2-cyclohexadiene increase the barriers for both the biradical-forming step and the product-forming step but decrease the product stability.