ChemInform Abstract: (4 + 2)Cycloadditions with Tetrabromocyclopropene: A New Synthetic Approach to Polyfunctionalized Indoles, Benzofuranes, and Benzothiophenes.

Abstract

4 + 2)Cycloadditions with Tetrabromocyclopropene: A New Synthetic Approach to Polyfunctionalized Indoles, Benzofuranes, and Benzothiophenes.-Diels-Alder reaction of 2-vinyl-substituted 5membered hetarenes such as (I) yields the functionalized benzo-fused derivatives (III) with no trace of possible regioisomers. The carbaldehydes (IV) are formed upon alkaline-catalyzed hydrolysis of (III). -(KEIL, J.-M.; KAEMPCHEN, T.; SEITZ, G.; Tetrahedron Lett. 31 (1990) 32, 4581-4584; Pharm.-Chem. Inst., Philipps-Univ., W-3550 Marburg/Lahn, Germany; DE)