Catalytic Synthesis Of Chiral N-heterocycles And Its Derivatives By Silver Complexes

Nitrogen heterocyclic compounds are important intermediates of drugs,pesticides,dyes and other chemical products.Asymmetric catalytic synthesis of heterocyclic compounds is challenging in the field of synthetic chemistry.The 1,3-dipolar [3+2] cycloaddition reaction is an important reaction for the synthesis of nitrogen heterocyclic compounds.Herein,catalytic asymmetric tandem conjugate 1,3-dipolar [3+2] cycloaddition with azomethine ylides were explored in the following research:Firstly,enantioselective synthesis of chiral heterocycle derivatives is an important and challenging topic in the field of synthetic chemistry.In this work,the first stereocontrolled dimerization-type homo-1,3-dipolar [3+2] cycloaddition reaction of glycine aldimino esters for creating new heterocycles bearing multiple stereogenic centers has been developed through the chiral phosphine ligand –involved silver catalysis.A variety of chiral imidazolidines could be obtained with high yields and good diastereoselectivities as well as excellent enantioselectivities by employing Xing-Phos as chiral P-ligand.In addition,the silver/Xing-Phos-catalyzed homo-1,3-dipolar [3+2] cycloaddition reaction is also a facile and novel protocol for catalytic polymerization of bifunctional glycine aldimino esters to give chiral poly(imidazolidine)s with a very narrow molecular-weight distribution.Secondly,the silver-catalyzed 1,3-dipolar cycloaddition of glycine aldimino esters with structurally diverse electrophiles is a powerful strategy for the construction of N-heterocycles,A highly diastereo-and enantioselective silver-catalyzed azomethine ylide-imine cycloaddition reaction of glycine aldimino esters with imines was developed for creating novel imidazolidines by employing our Xing-Phos and DTBM-Segphos as chiral P-ligand respectively.In addition,the discovery of two ligand-varied Ag catalysts that give controllable access to two diastereomeric products of a catalytic asymmetric transformation from a common starting material provided a synthetic strategy with switchable stereoselectivity.Notably,the chiral ligand-controlled syn-or anti-selective inversion of diastereo-and enantioselectivity could be applied to the synthesis of a variety of stereo-divergent 1-alkyl-2,5-substituted-imidazolidines with high yields and excellent enantioselectivities(up to 99% ee)as well as good diastereoselectivities(up to 99:1 dr)under mild reaction conditions.In conclusion,Asymmetric Catalyzed 1,3-dipolar [3+2] cycloaddition reaction of glycine aldimino esters for creating new heterocycles bearing multiple stereogenic centers with high yields and excellent enantioselectivities(up to 99% ee)as well as good diastereoselectivities(up to 99:1 dr)under mild reaction conditions.