The Synthesis Of New Chiral N, P Ligands And Their Applications In Enantioselective Allylic Alkylation

In the thesis,chiral N,P ligands in the enantioselective allylic alkylation were briefly reviewed.Subsequently,a series of new ligands 7a-7d and 8a-8d were synthesized and applicated in the above reaction.In the experiment section,pinocarvone 2 was obtained by ¹O₂ oxidation ofα-pinene.The obtained 2 was reacted with 1-Phenacylpyridinium iodide 3 to give 2-phenyl-5,6,7,8-tetrahydro-6,6-dimethyl-5, 7-methanoquinoline 4.4 reacted with n-BuLi at -78℃, followed by oxidation with O₂ to provided pyridylalcohols 5 and 6,and the absolute configuration of compound 6 had been confirmed by X-ray diffraction.Subsequently,compounds 5 and 6 were reacted with different configurations of BINOL and diaryl(N,N-diethylamino)phosphane to give ligands 7a-7d and 8a-8d,respectively.With ligands 7a-7d and 8a-8d in hand,we examined the effect of the new ligands in the palladium catalyzed allylic alkylation of 1, 3-diphenyl-2-propenyl acetate.The results showed that the catalytic effect of 7a-7d(25-100%yield,6-95%ee)were better than 8a-8d(35-100% yield,28-73%ee).After the screen of the bases,solvents,Pd and nucleophiles,we found that when CH₂(CO₂Me)₂ was used as nucleophile, CH₂Cl₂ as solvent,n-BuLi as base,[Pd(η³-C₃H₅)Cl]₂ as palladium precursor and 7b as ligand,excellent yield(up to 100%)and good enantiometric excess(up to 95%ee)were obtained.When ligand 8b was used in the substituted reaction,the yield and enantiometric excess were up to 100%and 73%,respectively.