10.1016/j.tet.2008.03.027
The study presents an investigation into the selective synthesis of functionalized cycloheptadienes through tandem enyne metathesis, utilizing Grubbs' catalyst to achieve regio- and site-selective ring expansion of dienes and substituted cyclopentenes. The research focuses on the influence of ring strain on the reactivity and selectivity of the metathesis process, elucidating the mechanistic aspects that contribute to the formation of 1,3-cycloheptadienes. The study also explores the reaction's scope and limitations, including the impact of different substituents and the potential for further functionalization of the synthesized cycloheptadienes. The findings provide valuable insights into the control of alkene stereoselectivity in enyne metathesis and the development of efficient synthetic strategies for complex molecule synthesis.
10.1039/c3cy00773a
The research aims to develop an efficient and sustainable method for synthesizing supported ruthenium nanoparticles (RuNP) within mesoporous silica materials (MCM-41, SBA-15, and HMS) to act as catalysts for oxidative Wittig coupling reactions. The study employs a mild synthesis approach by grafting aminopropyltriethoxysilane (APTES) onto the silica surfaces, which acts as both a reducing and protecting agent for the in situ reduction of RuCl3·H2O to form well-dispersed RuNP with an average size of 3 nm. These catalysts were tested in the one-pot alcohol oxidation–Wittig olefination reaction, where they demonstrated high catalytic activity and selectivity for the E product without the intermediacy of free aldehyde. The research concludes that the developed RuNP@silica materials are effective heterogeneous catalysts for this reaction, with Ru@MCM showing the highest selectivity due to its smaller pore size. The catalysts maintained 50%–60% of their original activity upon second use, indicating potential for recyclability.
