the gold‐catalyzed allene cycloisomerizations under aqueous micellar conditions is described. The polymers were prepared by ring‐opening cationic polymerization based on poly(2‐methyl‐2‐oxazoline) as hydrophilic segment and different hydrocarbon‐ or fluorocarbon‐based hydrophobic segments. The catalytic activity in the gold‐catalyzed allene cyclization is strongly dependent on the type of gold precursor
furanyl- and pyrrolyl-3-carboxamides from readily available 3-alkyne-1,2-diols and 1-amino-3-alkyn-2-ols using isocyanate as amido surrogate is demonstrated. The approach constitutes a successful unprecedented combination of heteropalladation and isocyanateinsertion, a new avenue for novel amide bond constructions. The mechanism likely involves a 6-membered oxaaminopalladacycle as the key intermediate.
Access to Polysubstituted Furan Derivatives via Cascade Oxy-palladation and Hydrocarbofunctionalization of Unactivated Alkenes
作者:Shivam Pandey、Rahul K. Shukla、Chandra M. R. Volla
DOI:10.1021/acs.orglett.3c01571
日期:2023.6.30
the synthesis of biologically relevant multisubstituted furans is a much-desired yet challenging task. Herein, we report an efficient and versatile strategy involving two different pathways for the construction of diverse polysubstituted C3- and C2-substituted γ-furanyl carboxylic acid derivatives. The synthetic approach for C3-substituted furans involves intramolecular cascade oxy-palladation of alkyne-diols
Catalytic and highly enantioselective Friedel–Crafts type reactions of heteroaromatic compounds with trifluoropyruvate and glyoxylate by a dicationic palladium complex
The highly enantioselective Friedel-Crafts alkylation of furan and thiophene derivatives with trifluoropyruvate, which have never provided the high level of asymmetric induction and yield until now, was achieved by using dicationic palladium complexes as Lewis acid catalysts. Moreover, glyoxylate instead of trifluoropyruvate as an electrophile led to complete change of regioselectivity with 2-trimethylsilylated furan, thiophene, and pyrrole derivatives to give the corresponding heteroarylated products in high yields and enantioselectivities. The respective products with trifluoropyruvate and glyoxylate could also be obtained via sequential catalytic reaction; intramolecular cyclization of alkynyldiols using cationic Au catalyst followed by Friedel-Crafts type reactions using dicationic Pd catalyst. (C) 2014 Elsevier Ltd. All rights reserved.
An efficient furan synthesis using heterogeneous catalysis
作者:Simon J. Hayes、David W. Knight、Melanie D. Menzies、Mark O’Halloran、Wen-Fei Tan
DOI:10.1016/j.tetlet.2007.08.102
日期:2007.10
A wide variety of 3-alkyne-1,2-diols have been found to undergo exceptionally clean 5-endo-dig cyclisations followed by dehydration at ambient temperature to give the corresponding furans in essentially quantitative yields when exposed to 10 mol % of 10%,w/w silver(1) nitrate absorbed on silica gel. (C) 2007 Elsevier Ltd. All rights reserved.