ChemInform Abstract: Single Bifunctional Ruthenium Catalyst for One‐Pot Cyclization and Hydration Giving Functionalized Indoles and Benzofurans.

Abstract

The cyclization of a range of aniline and phenol derivatives to indoles and benzofurans is presented. Advantages of this reaction are the use of only 2 mol% catalyst in most cases and the unprecedented ability of a cycloisomerization catalyst to perform hydration or deuteration in the same reaction. -(NAIR, R. N.; LEE, P. J.; REINGOLD, A. L.; GROTJAHN*, D. B.; Chem. Eur.

One-Pot Formation of Functionalized Indole and Benzofuran Derivatives Using a Single Bifunctional Ruthenium Catalyst

“…Our initial attempts to perform cycloisomerization reactions of homopropargylic alcohols [22] led to the conclusion that our ruthenium phosphine complexes formed carbene complexes which did not readily turn over to give required enol ethers as products. We then focused on the reactions of o-alkynylaryl amines and -phenols with a variety of functional groups on the nitrogen atom as well as the aromatic ring to give different substituted indole and benzofuran derivatives, as shown in Table 1 [23]. Eventually we realized that the catalyst has two potential applications-(1) anti-Markovnikov alkyne hydration and (2) terminal alkyne cyclization to give heteroaromatic compounds.…”