Series Of Reactions, Based On A Number Of The Adjacent Acetylenic Benzaldehyde

This dissertation mainly centers on methodology development for construction of natural product-like compounds via tandem reactions starting from 2-alkynylbenzaldehydes.(1) Synthesis of 1,2-dihydroisoquinolines via multi-component one-pot reaction of 2-alkynylbenzaldehyde,amine,zinc and allylic bromide.(2) The selective reaction of 2-(2-(alkynyl)benzylidene)malonate with indole promoted by t-BuOK or catalyzed by Sc(OTf)₃.(3) The tandem cyclization of(E)-4-(2-(phenylethynyl)phenyl)but-3-en-2-one with diethyl malonate.(4) The Aza-Diels-Alder reaction of methylenecyclopropanes with imines.A multi-component one-pot reaction of 2-alkynylbenzaldehydes,amines,zinc,and allylic bromide or benzyl bromide using the combination of Mg(ClO₄)₂/Cu(OTf)₂ as catalyst in THF/DCE(1:20) was discovered,which provided an efficient and practical route for the synthesis of functionalized 1,2-dihydroisoquinolines.Subsequently,2-(2-(alkynyl)benzylidene)malonate was synthesized starting from 2-alkybenzaldehyde,and the tandem reaction of 2-(2-(alkynyl)benzylidene)malonate with indole was investigated. (Z)-1-Benzylidene-3-(1H-indol-1-yl)-1H-indene-2,2(3H)- dicarboxylate was generated in the presence of t-BuOK at room temperature;whereas 3-((1H-indol-3-yl)(2 (alkynyl)aryl)methyl)-1H-indole was obtained when Sc(OTf)₃ was utilized as catalyst at 50℃.Meanwhile,the tandem reaction of(E)-4-(2-(phenylethynyl)phenyl)but-3-en-2-one with diethyl malonate was studied.Diethyl 1-(2-oxopropyl)-3-phenylnaphthalene-2,2(1H)-dicarboxylate was generated when AgOTf and pyrrolidine were utilized as the co-catalyzed.In addition,the FeCl₃-catalyzed aza-Diels-Alder reaction of methylenecyclopropane with imine was examined,which gave rise to the tetrahydroquinolines with a spirocyclopropyl ring in high yields.