Lewis Acid-catalyzed Asymmetric [3+2]-annulations Of Indoles And Aziridines

This thesis is focused on the development of an efficient method for building pyrroloindolines with multiple consecutive chiral centers.The asymmetric ring-opening reaction of aziridines is a very challenging work. The majority of previous studies are limited to the use of simple small alcohols as the nucleophile. In the presence of catalytic amount of Lewis acid and chiral binaphthyldiphosphosphine ligands, the reactions of indoles with aziridines provided hexahydropyrroloindolines in good yields( up to 98%) with an excellent diastereoselectivity(>20:1) and high enantioselectivity(99% ee). Mechanistically, the reaction involves an asymmetric electrophilic addition-cyclization cascade sequence featuring the generation of up to four stereogenic centers. The hexahydropyrroloindoline is the skeleton of many natural products and drugs, which has biological activities and medicinal value.The reaction is simple, highly stereoselective with an excellent atom-economy. In addition, the study of the asymmetric ring-opening reaction of aziridines contributes to the exploration of the ring-opening mechanism of aziridines.All the new products were characterized by 1H NMR, 13 C NMR, IR and HRMS. The relative configurations of some typical products were determined by COSY, analyses and X-ray crystallographic analyses.