Study On The Synthesis Of Chiral Guanidines And Their Application In Asymmetric Aldol Reactions

Guanidine, a neutral molecular containing three nitrogen atoms, is one of strongorganic bases. Substitutents, located on three nitrogen atoms in the structure ofguanidine, can be modified flexibly; and guanidines can indentify guest molecularsby hydrogen bondings. Based on these advantages, chiral guanidines, which aredesigned and synthsized elegantly, have a wide potential for asymmetric catalysis.In this thesis, we employed L-proline as chiral source react witho-phenylenediamine, and synthesized substituted L-prolinamide intermediate2-4.Chiral guanidines2-5and2-7can be prepared by the reaction of intermediate2-4with vilsmeier salts2-1and2-2.(1R,2R)-1,2-cyclohexane, which was obtained viaresolution of (±)-trans-1,2-cyclohexanediamine, react with imidoyl chloridecompounds containing Benzo thiadiazine skeleton, and formed chiral guanidines9a-9c. These chiral guanidines are potential hydrogen bonding donors, and they havebeen characterized by1H NMR,13C NMR and HRMS.In the aldol reaction of cyclohexanone with p-nitrobenzaldehyde, preliminaryresults showed slovents, such as DMF and DMSO, have a apparent effect ondiastereoselectivity and stereoselectivity of corresponding products when the amountof chiral guanidine2-7is5mol%, and reaction temperature is30℃. Screening andoptimization of reaction conditions are going on in our laborotary.