Pd-Catalyzed Intramolecular Cyclization-Thiocarbonylation Cascade Using Thioesters

A Pd-catalyzed intramolecular cyclization-thiocarbonyla-tion cascade using thioesters is described. The developed cascade reac-tion afforded chromane, coumaran, indoline, and oxindole derivatives with a chiral quaternary carbon atom at the benzylic position in high to excellent yields. Relative to those observed in the previously reported relevant cascade using TIPSSPh, the yields with thioesters are almost the same or higher, depending on the substrate. Moreover, the use of thioesters significantly reduces the reaction time to less than one hour. Therefore, AcSPh is advantageous over TIPSSPh in terms of reaction time, atom economy, and cost effectiveness.

Automated summary

A Pd-catalyzed intramolecular cyclization-thiocarbonylation cascade using thioesters is developed, yielding chromane, coumaran, indoline, and oxindole derivatives with a chiral quaternary carbon atom at the benzylic position in high to excellent yields. Compared to the previously reported method using TIPSSPh, the use of thioesters in this cascade reaction provides similar or higher yields, depending on the substrate, with significantly reduced reaction time.