Synthesis Of Isochroman And Naphthalene Derivatives Based On Catalytic Cascade Reaction Of Alkynes Through Metal Carbene Intermediates

Metal carbene is an important class of reaction intermediates and has been widely used in modern organic synthesis reactions.In recent years,carbene/alkyne metathesis cascade reaction as a kind of high-efficiency bonding synthesis method has received great attention in the field of chemical research,especially in the asymmetric synthesis of heteropolycyclic compounds.This paper mainly focused on two different catalytic cascade reactions,including chiral birhodium-catalyzed nitrene/alkyne metathesis cascade reaction;and gold-catalyzed tandem reaction of alkyne and diazo compounds to construct Isochroman and Naphthalene Derivatives,which are listed below:Part Ⅰ:An asymmetric chiral dirhodium earboxylates-catalyzed nitrene/alkyne metathesis(NAM)cascade reaction of alkyne-tethered sulfamates has been developed,which provides a general access for the synthesis of tricyclic N-heterocycles in good yields and excellent enantioselectivity.The chiral dirhodium catalyst not ouly promotes the nitrene/alkyne metathesis(NAM)to generate the key intermediate,α-imino metal carbene,but also was responsible for the observed asymmetric induction in the terminating[2,3]-sigmatropic rearrangement of oxonium ylide intermediate.Part Ⅱ:A gold-catalyzed cascade cyclization of alkyne and diazo compounds was studied.It was found that the diazo group acts as a nucleophilic group to attack the gold activated alkyne,releasing one molecule of nitrogen to form vinyl carbene intermediate,and then intercepted by the electron-rich aromatic rings to form a naphthalene product.