An efficient furan synthesis using heterogeneous catalysis
摘要:
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.
Expedient Syntheses of β-Iodofurans by 5-endo-dig Cyclisations
作者:Sean P. Bew、Gamila M. M. El-Taeb、Simon Jones、David W. Knight、Wen-Fei Tan
DOI:10.1002/ejoc.200700681
日期:2007.12
yields of the corresponding β-iodofurans. The necessary precursors are available from a number of different approaches, notably regioselective bis-hydroxylation of conjugated enynes and the addition of acetylides to α-hydroxy carbonyl groups. The initial iodofurans can be homologated using a number of strategies, ranging from various transition metal-catalysed couplings to halogen-metal exchange and subsequent
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.
On the highly stereoselective addition of lithio-acetylides to α-hydroxy-ketones
作者:Damian Dunford、Mathilde Guyader、Simon Jones、David W. Knight、Michael B. Hursthouse、Simon J. Coles
DOI:10.1016/j.tetlet.2008.02.032
日期:2008.3
Addition of 2 equiv of a lithio-acetylide to an unprotected alpha-hydroxy ketone is extremely stereoselective in examples where the two ketone substituents are relatively large. (C) 2008 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.