Trisubstituted alkenes featuring aryl groups:stereoselective synthetic strategies and applications

In recent years,the synthesis and application of alkenes have attracted increased attention.Triphenylethenes(TriPEs)have lower molecular torsion than tetraphenylethenes(TPEs),which helps to balance the degree of conjugation and the aggregation-induced emission(AIE)effect.The geometry of double bonds has a significant impact on luminescence.Therefore,it is essential to provide a comprehensive summary of the stereoselective synthetic strategies for trisubstituted alkenes.In this review,common strategies for the stereoselective synthesis of alkenes are described,with an emphasis on the origin of stereoselectivity and the types of substrates.In addition,the AIE properties of TriPE and its applications in optoelectronic devices,stimuli-responsive materials,sensors,and therapies were discussed.

Aggregation-enabled alkene insertion into carbon–halogen bonds

Molecular aggregation affects the electronic interactions between molecules and has emerged as a powerful tool in material science.Aggregate effect finds wide applications in the research of new physical phenomena;however,its value for chemical reaction development has been far less explored.Herein,we report the development of aggregation-enabled alkene insertion into carbon–halogen bonds.The spontaneous cleavage of C–X(X=Cl,Br,or I)bonds generates an intimate ion pair,which can be quickly captured by alkenes in an aggregated state.Additional catalysts or promoters are not necessary under such circumstances,and solvent quenching experiments indicate that the aggregated state is critical for achieving such sequences.The ionic insertion mode is supported by mechanistic studies,density functional theory calculations,and symmetry-adapted perturbation theory analysis.Results also show that the non-aggregated state may quench the transition state and terminate the insertion process.