Substitution,Elimination And Rearrangement Reactions Of Alkylamines

C-N bond widely exists in organic molecules and the transformation of C-N bond is one of the topics in organic chemistry.The cleavage of C-N bond is not easy because of the poor leaving ability of the NH2,especially the alkylamines.To break the C-N bond of alkylamines,there are two general methods.The first one is activated carbon-nitrogen bond.One or two electron-withdrawing groups is linked on the nitrogen or changing the amines to ammonium salts to activate the C-N bond,thus,the cleavage is much easier.The second method is the catalysis of metal.This way is more popular and allylic amines are explored deeply.Direct enantiospecific substitution of primary a-aminoalkylferrocenes via Lewis acid catalysis was developed.Alkenes were obtained through the elimination of tertiary amines activated by benzyne.Aryne-mediated[2,3]-sigmatropic rearrangement of propargylic amines was studied to synthesize conjugated dienes and allenes.The article was divided into four parts.Chapter one:Review of nucleophilic substitution of primary alkylamines and reactions of tertiary amines activated by arynes.Firstly,the substitution reaction of primary alkylamines was introduced.Primary allylic amines were studied widely from racemic to chiral forms to kinetic resolution.Nucleophilic substitution reactions of primary benzylamines were also reported but the substrates were special.Secondly,the character and reaction models of aryne were simply overviewed.Lastly,the cleavage of C-N bond of tertiary amines activated by aryne were reviewed.This part was also divided into four:the rearrangement reactions,ring-opening reactions of nitrogen-containing heterocyclic compounds,reactions of aromatic amines with arynes and nucleophilic substitution of chiral tertiary amines.Chapter two:Direct enantiospecific substitution of primary α-aminoalkylferrocenes via Lewis acid-catalyzed C-N bond cleavage.Nucleophilic substitution of chiral primary a-aminoalkylferrocenes was conducted.The reaction was simply catalyzed by Lewis acid and chiral products were gained with excellent retention of configuration via effective chirality transfer.Different nucleophiles were tried and indoles,active methylene compounds,sulfur nucleophiles and electron-rich aromatic compounds were included.Structurally diverse ferrocenyl-derived compounds were obtained with high yields and ee.Primary amines were used and NH2 was the leaving group with a small mass.So the reaction possessed excellent atom economy.Chapter three:Alkenes synthesis via the elimination of tertiary amines activated by benzyne.Alkenes were not only widely existed structural motifs in lots of nature products,but also served as a foundation for a broad range of chemical transformations.Alkenes were obtained through the elimination of tertiary amines activated by benzyne.The reaction followed the Hofmann rule and terminal alkenes were preferred in common.For the internal alkenes,Z-isomers were preferred.The reaction mechanism was E2 which was similar to the Hofmann elimination.The reaction was also underwent smoothly with N-containing cyclic compounds.Chapter four:Aryne-mediated[2,3]-σ rearrangement of propargylic amines.The[2,3]-σ rearrangement of propargylic amines was seldom researched and two ways were developed before.One was via the base catalysis of ammonium salts and another one was via metal catalysis.The ammonium salts were generated in situ by the combination of amines and arynes.Then ylides were obtained and[2,3]rearrangement took place lastly.For the terminal alkynes,conjugated dienes were gained and allenes were obtained for the internal alkynes.The reaction conditions were mild and room temperature was enough.