Highly efficient heterogeneous synthesis of benzofurans under aqueous condition
摘要:
Highly efficient organic reactions in water are important for designing environmental-friendly and low cost synthetic processes. Herein, we demonstrate an intermediate-in-water strategy for the heterogeneous synthesis of benzofurans in aqueous media. The cyclization reaction of 2-(phenylethynyl)phenol to 2-phenylbenzofuran cannot proceed in pure water. However, this reaction can be efficiently promoted by the formation of sparingly soluble intermediate in the presence of alkaline. Quantitative conversion of a variety of substrates to benzofuran derivatives has been achieved in the absence of noble metal catalyst. Other remarkable features including easy-isolation and purification of product, along with wide range of functional group tolerance render the methodology promising in the realm of green-synthesis. (C) 2014 Elsevier Ltd. All rights reserved.
Gold-Catalyzed Cyclizations of (o-Alkynyl)phenoxyacrylates with External Nucleophiles: Regio- and Stereoselective Synthesis of Functionalized Benzo[b]oxepines
摘要:
A catalytic approach to benzo[b]oxepines with high stereoselectivity by Au-catalyzed cyclization of (o-alkynyl)phenoxyacrylates with various nucleophiles under mild reaction conditions has been developed. Notably, the use of vinyl ether instead of alcohol could afford the same benzoxepines. The reaction may proceed by Au-catalyzed oligomerization of vinyl ether to release the alcohol, which then reacts with (o-alkynyl)phenoxyacrylates to furnish the benzoxepines.
A concise approach for the synthesis of 3-iodoindoles and 3-iodobenzo[b]furans via Ph3P-catalyzed iodocyclization
作者:Yin-Long Li、Jian Li、Sheng-Nan Yu、Ji-Bo Wang、Yan-Min Yu、Jun Deng
DOI:10.1016/j.tet.2015.09.005
日期:2015.10
A variety of 3-iodoindole and 3-iodobenzo[b]furan derivatives were conveniently prepared from the corresponding 2-alkynylanilines and 2-alkynylphenols through Ph3P-catalyzed iodocyclization in the presence of N-iodosuccinimide (NIS). This protocol provides a rapid access to 3-iodoindoles and 3-iodobenzo[b]furans in good to excellent yields under mild conditions.