Stereocontrolled construction of the dihydrothiopyrano[2,3-b]indole skeleton via an organocatalyzed asymmetric cascade sulfa-Michael-aldol reaction

摘要

We have developed an organocatalyzed asymmetric cascade sulfa-Michael-aldol reaction between 2-mercaptoindole-3-carbaldehydes and enals, which provides efficient access to the stereocontrolled construction of dihydrothiopyrano[2,3-b]indole skeletons. Under the catalysis of chiral diphenylprolinol TMS ether, the reactions ran smoothly to give the corresponding synthetically useful and pharmaceutically valuable dihydrothiopyrano[2,3-b]indoles in high yields and with 64-96% ee.