Synthesis of Chiral 3-Substituted Benzoquinone Compounds Through Asymmetric Catalytic Tandem Reaction with Chiral Phosphoramide as Catalyst

We used thiophosphoramide as a catalyst, which was synthesized after several simple reactions of trans-1,2-diphenyl-ethylenediamine, aromatic aldehydes and arylalkyl zincs or diethylzinc as reactants, to synthesize chiral 3-substituted benzoquinone compounds with important biological activity, through 1,2-addition/lactoneization tandem reaction. The raw materials are cheap and easy to obtain, the catalytic efficiency is high. The yield and e.e. value can be guaranteed to be as high as 80% simultaneously. Despite the large amount of catalyst, the ligand is very convenient to recycle and reuse in this system. At the same time, we speculate on the reaction mechanism, and believe that the quaternary transition state and the six-element transition state formed by the reaction process are beneficial to improve the enantioselectivity of the reaction.