Waste-Free Catalytic Propargylation/Allenylation of Aryl and Heteroaryl Nucleophiles and Synthesis of Naphthopyrans
作者:J. McCubbin、Costa Nassar、Oleg Krokhin
DOI:10.1055/s-0030-1260146
日期:2011.10
pyrroles, as well as methoxy-substituted benzenes and naphthalenes. Reaction with 2-naphthol affords substituted naphthopyrans as products. Preliminary evidence suggests a Friedel-Crafts-like substitution mechanism, which occurs via an in situ generated carbocation. organocatalysis - boronic acids - propargylic alcohols - Friedel-Craftsreaction
Iron-Catalyzed Direct Synthesis of Densely Substituted Benzofurans and Naphthopyrans from Phenolic Compounds and Propargylic Alcohols
作者:Feng-Quan Yuan、Fu-She Han
DOI:10.1002/adsc.201200804
日期:2013.2.1
propargylic alcohols in the presence of 5 mol% of iron(III) chloride hexahydrate (FeCl3⋅6 H2O) catalyst. On the other hand, pyran derivatives were obtained exclusively when tertiary propargylic alcohols were employed. Mechanistic studies revealed that presumably due to the discriminated steric effect of secondary and tertiary propargylic alcohols, the Fe-catalyzed Friedel–Crafts (F–C) reaction of phenols
cyclization between propargyl alcohols and ambident enols such as naphthols, 4-hydroxy coumarin, cyclohexane-1,3-dione, 5,5-dimethylcyclohexane-1,3-dione is described using Ca(OTf)2 under solvent free conditions. The reaction proceeds through a cascade annulation which involves an etherification, Claisen type rearrangement, allene formation and endocyclization. Further, we extended this method to the synthesis