One-pot synthesis of 2,2′-bisbenzofurans using cuprous chloride as a catalyst
摘要:
A variety of novel 5,5'-disubstituted-2,2'-bisbenzofuran derivatives were synthesized by treatment of 4-substituted-2-(2-trimethylsilylethynyl)phenyl tert-butyldimethylsilyl ether analogues with Cud I as a catalyst in 62-82% isolated yields. This novel strategy provides a straightforward and simple pathway for the preparation of 2,2'-bisbenzofuran derivatives of interest in life and material sciences. (c) 2013 Elsevier Ltd. All rights reserved.
Convenient and Highly Efficient Routes to 2
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‐Chromene and 4‐Chromanone Derivatives: Iodine‐Promoted and
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‐Toluenesulfonic Acid Catalyzed Cascade Cyclizations of Propynols
A convenient strategy is presented for the easy preparation of a series of 2H‐chromenes under mild conditions through iodocyclization of readily accessible propynols. In addition, various 4‐chromanones can be synthesized through a p‐toluenesulfonicacidcatalyzedcascadecyclization with high efficiency (yields up to 99 %). Our developed reaction systems are proven to have good functional‐group applicability
BF<sub>3</sub>·Et<sub>2</sub>O-Promoted Cleavage of the C<sub>sp</sub>–C<sub>sp2</sub> Bond of 2-Propynolphenols/Anilines: Route to C2-Alkenylated Benzoxazoles and Benzimidazoles
A novel BF3 center dot Et2O-promoted tandem reaction of easily prepared 2-propynolphenols/anilines and trimethylsilyl azide is developed to give C2-alkenylated benzoxazoles and benzimidazoles in moderate to good yields. Most reactions could be accomplished in 30 min at room temperature. This tandem process involves a C-sp-C-sp2 bond cleavage and a C-N bond formation. Moreover, both tertiary and secondary propargylic alcohols with diverse functional groups were tolerated under the mild conditions.