Synthesis of Azomethine Imines Using an Intramolecular Alkyne Hydrohydrazination Approach
摘要:
Azomethine imines can be accessed upon heating appropriate alkynylhydrazide precursors. This simple thermal hydroamination approach allows the formation of five- and six-membered dipoles in modest to excellent yields. The structure of the acyl group is important to minimize side reactions and allow the isolation of the azomethine imines by column chromatography.
of unactivated alkyl chlorides with tethered alkenes. The cleavage of strong C(sp3)−Cl bonds is mediated by a highly nucleophilic low‐valent cobalt or nickel intermediate generated by visible‐light photoredox reduction employing a copper photosensitizer. The high basicity and multidentate nature of the ligands are key to obtaining efficient metal catalysts for the functionalization of unactivated alkyl
A Gold-Catalyzed Cascade Reaction Involving an Unusual Intramolecular Redox Process
作者:José Barluenga、Amadeo Fernández、Félix Rodríguez、Francisco J. Fañanás
DOI:10.1002/chem.200901557
日期:2009.8.17
Gold catalysis: Secondary 5‐hexyn‐1‐ol derivatives react with indoles and other heteroaromatic compounds under gold‐catalyzed conditions to give the corresponding ketone derivative (see scheme) through a cascade reaction involving an initial intramolecular hydroalkoxylation reaction of the triple bond followed by an intermolecular hydroarylation reaction and an unusual intramolecular Oppenauer‐type
An efficienttandemcatalysis method is achieved for the direct conversion of alcohol-containing alkynyl anilines to valuable chiral 2,3-fused tricyclic indoles. This method relies on a tandem indolization followed by enantioconvergent substitution of alcohols via borrowing hydrogen to construct two rings in one step, enabled by relay and cooperative catalysis of a chiral iridium complex with a chiral
A Practical Synthesis of Rosefuran. Furans from Acetylenes and Allyl Alcohols
作者:Barry M. Trost、John A. Flygare
DOI:10.1021/jo00084a026
日期:1994.3
A new atom-economical synthetic strategy for the synthesis of furans emerges from beta,gamma-unsaturated ketones which are readily available from acetylenes and allyl alcohols by simple additions in the presence of a ruthenium catalyst. Dihydroxylation using catalytic osmium tetraoxide creates a diol that is remarkably prone to cyclize to furans in the presence of an acid catalyst. The novelty of this synthesis lies in the overall strategy whereby furans are available in two steps from allyl alcohols and acetylenes with only water as the byproduct. A straightforward synthesis of the prized fragrance of oil of rose, rosefuran, from propargyl bromide, acetone, and 1-buten-3-ol in 23% overall yield illustrates the utility of this new strategy.