Se...O Interaction Catalyzed Cyanosilication Of Ketones And Cascade Cyclization

Se…O interaction is one of the chalcogen bonding interactions.Currently,because of the chalcogen bonding interaction is very weak,only few chalcogen bonding catalysis approaches have been reported.These works have some limitations,such as high catalyst-loading,low catalytic efficiency,and the lack of new types of reactions.Based on Se…O interaction catalysis,this thesis achieved cyanosilylation of ketones using ppm-level catalyst loading.In addition,cascade cyclization reactions catalyzed by Se…O interaction were realized.This thesis mainly includes two parts:Part 1.Cyanosilylation of ketones catalyzed by Se…O interactionIn this thesis,a chalcogen-bonding catalysis approach to cyanosilylation of a broad range of ketones can be achieved even using as low as parts per million(ppm)level catalyst loading while the reactions were completed within several minutes at room temperature.This chalcogen-bonding catalysis gives high turnover frequency numbers.The interaction mode was demonstrated by NMR experiments and X-ray crystal structures.The control experiments and inhibition experiments showed that Se…O bonding interaction plays a key role in this cyanosilylation reaction.Part 2.Cascade cyclization reactions catalyzed by Se…O interactionCatalysis of complex organic reactions by Se…O bonding interaction has been a difficult scientific problem.To this end,we realized the cascade cyclization reaction between specific cyclopropanes and unsaturated compounds.The Se…O interaction activates the carbonyl group on a specific cyclopropane substrate,thereby leading to the ring opening and rearrangement of the three-membered ring.Under the activation of the Se…O interaction,the rearrangement product can undergo a cyclization reaction with ?,?-unsaturated ketone.Finally,the Se…O interaction catalyzes the continuous cyclization reaction between cyclopropane and unsaturated ketone to give a polycyclic product.