Studies On The Redox-nuetral Reaction And1,6-conjugate Addition Reaction Of Para-quinone Methides

Carbon-carbon bond formation is a key step in the construction of complex compound molecules.The conjugate addition of carbon nucleophiles to electron-deficient olefins is one of the most important reactions for carbon-carbon bond formation.Compare to well explored 1,4-conjugate addition ofα,β,γ,δ-diunsaturated olefins to carbon nucleophiles,the 1,6-conjugate addition offers great opportunities for further in-depth studies.In recent years,the 1.6-conjugated addition of para-Quinone Methides（p-QMs）to build complex frameworks has drawn much attention because their unique reaction activities.However,1.6-conjugated addition mediated cascade reactions of p-QMs as well as quaternary carbons formation remains to be highly desirable.In this thesis,the borane catalyzedβ-functionalization of tertiary amines using p-QMs via borrowing hydrogen strategy was developed.Additionally,Fe Cl₃catalyzed 1,6-conjugate allylation reaction of p-QMs from isatin was also disclosed to construct 3,3-disubstituted Oxindoles Compounds.Firstly,the intermolecular redox-neutralβ-alkylation of tertiary amines catalyzed by B（C₆F₅）₃was developed.By using borrowing hydrogen strategy,an“oxidation/1,6-conjugate addition/reduction”cascade reaction of p-QMs and tertiary amines was achieved,and a diverse array ofγ-diaryl substituted tertiary amines could be prepared in good yields.This metal-free transformation required no external oxidants,which is a novel green approach for directβ-functionalization of tertiary amines.1,6-conjugate allylation reaction of p-QMs using active allylic nucleophiles is an efficient method for the synthesis of allylic diarylmethanes,but the application of this reaction in the synthesis of allylic diarylmethanes that bearing quaternary carbons was rarely reported.In the second part of this thesis,a Lewis acid catalyzed 1,6-conjugate allylation reaction utilizingα-methylstyrenes and p-QMs derived from isatins was realized.A series of 3,3-disubstituted oxindole derivatives were synthesized in high yields.This reaction utilized inactive allylic nucleophiles,which provide a new solution for the synthesis of allylic diarylmethanes that bearing quaternary carbons.