Study On The Synthesis Of Polysubstituted Benzenes By α, α-dycyanoolefins

Polysubstituted benzenes are highly useful entities, which are widelyused in industry, pharmacy and laboratory. Because the complex structure of aromaticcompounds, preparation of the regioselective and highly substituted aromaticcompounds is one of the challenging problems in organic synthesis. How to synthesisPolysubstituted benzenes and their derivatives are people interested. SynthesizePolysubstituted aromatic in efficiently and economically becomes interest that manyresearch group towards.Firstly, we studied the molecule of the vinylogous Michael addition product andfound that polysubstituted benzene was obtained through intermolecular nucleophilicreaction. The final structure was confirmed by NMR, IR, Single-XRD diffraction,HRMS. With the optimized reaction conditions in hand, several solvents and base havebeen investigated, CH₃CN and NaOEt(100%) were selected as the best.Secondly, We found the vinylogous Michael addition and aromatization of additionproducts can be processed in one pot and polysubstituted benzenes can be obtained withsatisfying yield(76%). From the synthetic chemist's point of view, one-pot proceduresstarting with simple, readily available substrates provide ideal strategies for regioselectiveformation of substituted benzene. Finally, we studied their characteristic of liquid crystaland found polysubstituted benzenes have potential to be useful LC molecule. We found anew method that polysubstituted benzenes could obtained from aldehyde and ketone.Lastly, we studied crystal structures of compound 4b, 4m and 4k. We found that allthese crystal exist hydrogen bond N—H...N and the dimers formed by paird hydrogenbonds. The molecule of 4b are linked by N—H...N and N—H...O hydrogen bonds. Themolecule of 4m are linked by N—H...N and C—H...Ï€interactions. The molecule of 4kare linked by C—H...O hydrogen bonds and C—H...Ï€interactions.In this paper, we give an efficient method for the synthesis of polysubstitutedbenzenes through the tandem vinylogous Michael reaction ofα,α-dycyanoolefins and α,β-nitroolefins.