Indoline-2-thiones (5) were applied as 1,3-dinucleophiles in a tandem reaction with Baylis-Hillman adduct acetates (4) to give novel tetrahydrothiopyrano[2,3-b]indole skeletons (6). The effect of different solvents, bases, and catalysts on the yields and stereochemical outcome was studied in detail. The results indicated that acetonitrile as solvent and K 2CO3 as base, under reflux conditions, were the optimum conditions. Products 6a-6l were obtained in high diastereoselectivity and yield (up to 94%).
- Baylis-Hilman adduct acetates
- Tandem reaction