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
high-efficiency, and atom-economical synthesis of valuableorganophosphoruscompounds via cascade annulation of propargylic alcohols with diphenylphosphine oxide is described. This protocol, which has a good functional-group compatibility and insensitivity to an ambient atmosphere, provides a simple and direct pathway to the products, organophosphoruscompounds, in good yields under mild conditions. The method
A simple and efficient method for the synthesis of tricyclic chromones has been developed. In this approach, tricyclic chromones were synthesized from a diverse range of phenols and alkynes through a Sonogashira coupling and subsequent gold-catalyzed intramolecular dominocyclization.
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.
Rhodium(III)-Catalyzed Direct C-2 Olefination of Unactivated Indoles Utilizing OH/NH<sub>2</sub>as Directing Group
作者:Chen-Yu Tang、Yuan Tao、Xin-Yan Wu、Feng Sha
DOI:10.1002/adsc.201300930
日期:2014.2.10
AbstractOxidative C‐2 olefination of indoles/pyrrole via rhodium(III)‐catalyzed direct CH bond activation is reported. Phenolic OH and aniline NH2 units were revealed to be effective chelating groups to activate the aryl CH bond. The reactions proceeded with excellent selectivity and high functional group tolerance, furnishing 2‐vinylindoles/2‐vinylpyrroles in good yields.magnified image