Reaction of 3‐(1‐Arylsulfonylalkyl)‐indoles with Easily Enolisable Derivatives Promoted by Potassium Fluoride on Basic Alumina
作者:Roberto Ballini、Alessandro Palmieri、Marino Petrini、Rafik R. Shaikh
DOI:10.1002/adsc.200700410
日期:2008.1.4
Active methylene compounds and nitro derivatives react with 3-(1-arylsulfonylalkyl)-indoles in the presence of potassiumfluoride on basic alumina at room temperature leading to the corresponding adducts in good yields. Under basic conditions, sulfonylindoles suffer elimination of arenesulfinic acid leading to an intermediate vinylogous imine that promptly adds stabilized carbanions. The obtained 3-indolyl
Sulfonyl indoles act as effective precursors of vinylogous imino derivatives in the reaction with nitroalkanes under basicconditions leading to the corresponding nitro indoles in good yield. This procedure represents an effective option to the classical conjugateaddition of indoles to nitroalkenes.
H-Bonding Organocatalysed Friedel-Crafts Alkylation of Aromatic and Heteroaromatic Systems with Nitroolefins
作者:Raquel P. Herrera、Alfredo Ricci、Gabriella Dessole
DOI:10.1055/s-2004-832844
日期:——
Catalytic amounts (10 mol%) of bis-arylureas and -thioureas promote the Friedel-Crafts alkylation with nitroolefins of aromatic and heteroaromatic N-containing derivatives. A sizeable improvement of the yields is noticed on running the reactions in the absence of solvent. When applied to indoles this protocol provides in good to excellent yields and with high selectivity the corresponding Michael adducts