215794-65-3Relevant academic research and scientific papers
From Benzofurans to Indoles: Palladium-Catalyzed Reductive Ring-Opening and Closure via β-Phenoxide Elimination
Perego, Luca A.,Wagschal, Simon,Grüber, Raymond,Fleurat-Lessard, Paul,El Ka?m, Laurent,Grimaud, Laurence
, p. 151 - 159 (2018/12/05)
Benzofurans can undergo ring-opening by a palladium-catalyzed process resulting in C?O bond breaking. Benzofuran-tethered 2-iodoanilines give synthetically interesting 2-(3-indolylmethyl)phenols in an overall reductive process. Mechanistic studies suggest that this unusual reaction proceeds by carbopalladation of benzofuran giving a 3-palladated 2,3-dihydrobenzofuran intermediate, which then fragments by an uncommon trans-elimination of the phenoxide group β to the metal. In this transformation, N,N-diisopropylethylamine (DIPEA) acts as a base and as a reducing agent: it regenerates palladium(0) from palladium(II), thus allowing catalytic turnover. (Figure presented.).
A new copper(I)-catalyzed cycloetherification/acid-catalyzed allylic nucleophilic substitution for one-pot synthesis of 2-substituted benzofurans
Li, Xin,Xue, Jijun,Chen, Rui,Li, Ying
, p. 1043 - 1046 (2012/06/04)
A new copper(I)-catalyzed cycloetherification followed by an acid-catalyzed allylic nucleophilic substitution have been developed for the one-pot synthesis of 2-substituted benzofurans. This one-pot reaction proceeds efficiently under extremely mild conditions with simple and inexpensive catalysts, providing diversely substituted benzofurans in good to excellent yields. Georg Thieme Verlag Stuttgart. New York.
A novel synthesis of 2-functionalized benzofurans by palladium-catalyzed cycloisomerization of 2-(1-hydroxyprop-2-ynyl)phenols followed by acid-catalyzed allylic isomerization or allylic nucleophilic substitution
Gabriele, Bartolo,Mancuso, Raffaella,Salerno, Giuseppe
supporting information; experimental part, p. 7336 - 7341 (2009/04/18)
(Chemical Equation Presented) A novel two-step synthesis of 2-hydroxymethylbenzofurans 3 and 2-alkoxymethylbenzofurans 4-6, based on palladium-catalyzed cycloisomerization of 2-(1-hydroxyprop-2-ynyl)phenols 1 under basic conditions to give 2-methylene-2,3-dihydrobenzofuran-3-ols 2, followed by acid-catalyzed isomerization or allylic nucleophilic substitution with alcohols as nucleophiles, is reported. Cycloisomerization reactions leading to 2 (80-98% yields) were carried out at 40°C in MeOH as the solvent, in the presence of a base and catalytic amounts of PdX2 + 2KX (X = Cl, I). Isomerization reactions of 2 readily occurred at 25-60 °C in DME as the solvent, with H2SO4 as the proton source, to give 2-hydroxymethylbenzofurans 3 in 65-90% yields. In a similar manner, allylic nucleophilic substitution reactions of 2 with ROH as nucleophiles [carried out at 25-40°C in ROH (R = Me) or ROH-DME mixtures (R = Bu, Bn) in the presence of H2SO4] afforded 2-alkoxymethylbenzofurans 4, 5, and 6 (R = Me, Bu, and Bn, respectively), in 65-98% yields.
