Synthesis of 2-Substitued Indoles via Pd-Catalysed Cyclization in an Aqueous Micellar Medium

The synthesis of 2-substituted indoles starting from the corresponding unprotected 2-alkynylanilines was made possible in 3% TPGS-750-M water using Pd(OAc)(2) alone as the catalyst. The reaction was sensitive to the heating mode respect to the nature of the starting material as, in many cases, convectional heating was better than microwave dielectric heating. The MW (microwave) delivery mode had also an influence in the formation of by-products and, consequently, product yields. A tandem Sonogashira-cyclisation reaction was also accomplished using Pd(OAc)(2)/Xphos in the nanomicellar water environment.

Automated summary

The synthesis of 2-substituted indoles from unprotected 2-alkynylanilines using Pd(OAc)(2) catalyst in 3% TPGS-750-M water was found to be sensitive to the heating mode and the MW delivery mode, with convectional heating often proving more effective than microwave dielectric heating. Additionally, a tandem Sonogashira-cyclisation reaction was successfully achieved in the nanomicellar water environment with Pd(OAc)(2)/Xphos.