Iron-Catalyzed Synthesis of Functionalized 2H-Chromenes via Intramolecular Alkyne−Carbonyl Metathesis
摘要:
An iron-catalyzed intramolecular alkyne-aldehyde metathesis strategy of the alkynyl ether of salicylaldehyde derivatives has been developed which works under mild reaction conditions to produce the functionalized 2H-chromene derivatives. This protocol is compatible toward a wide range of functional groups, such as methoxy, fluoro, chloro, brow, and phenyl groups. This method provides an atom-economical and environmentally friendly approach for the synthesis of a series of substituted 2H-chromenes.
N-Heterocyclic Carbene-Catalyzed Cascade Reaction Involving the Hydroacylation of Unactivated Alkynes
作者:Akkattu T. Biju、Nathalie E. Wurz、Frank Glorius
DOI:10.1021/ja102130s
日期:2010.5.5
The N-heterocyclic carbene (NHC)-catalyzed hydroacylation of unactivated alkynes to provide alpha,beta-unsaturated ketones is reported. In addition, a rare case of an efficient and selective dually NHC-catalyzed cascade reaction involving the hydroacylation of alkynes and a subsequent intermolecular Stetter reaction allows the formation of chromanones containing a 1,4-diketone moiety.
Mechanistic details of transformations catalyzed by N‐heterocyclic carbenes (NHC) are currently of great interest, targeting questions on the active catalyst in operation and the structure and reactivity of key intermediates. These mechanistic studies are driven by the need to understand the big impact of subtle changes on the catalyst system on its reactivity, as well as to clarify the situation around
Boron trifluoride–etherate in fluorinated alcohols: A powerful promoter system for intramolecular alkyne–aldehyde metathesis of o-(3-arylpropargyloxy)benzaldehydes
作者:Arup Jyoti Das、Runjun Devi、Sajal Kumar Das
DOI:10.1016/j.tetlet.2018.10.040
日期:2018.11
Boron trifluoride-etherate (BF3 center dot OEt2) in 2,2,2-trifluoroethanol (TFE) was found to be a highly efficient promoter system for the intramolecular alkyne-aldehyde metathesis of o-(3-arylpropargyloxy)benzaldehydes. The reaction produces the corresponding 3-aroyl-2H-chromenes in excellent yields under metal free conditions. (C) 2018 Elsevier Ltd. All rights reserved.