Electrocyclization of cis-dienals in organic synthesis: a new and versatile synthetic method for the preparation of aryl- and heteroaryl-fused coumarins
作者:Yung-Son Hon、Tze-Wei Tseng、Chia-Yi Cheng
DOI:10.1039/b912887e
日期:——
Benzo-, furo-, thieno-, and pyrido[f]coumarins were prepared by generating the 2H-pyran-2-one moieties from the oxidation of the corresponding 2H-pyran rings, which were formed in situ from the electrocyclization of cis-dienals.
Visible-light promoted oxidative cyclization of cinnamic acid derivatives using xanthone as the photocatalyst
作者:Bin Zhao、Bo Xu
DOI:10.1039/d0ob02417a
日期:——
coumarin derivatives via a tandem double bond isomerization/oxidative cyclization of cinnamic acids. Inexpensive and stable xanthone was used as the photocatalyst, and readily available Selectfluor was used as the oxidant. This method tolerates a wide range of functional groups and offers excellent chemical yields in general. Besides, the photocatalytic oxidative cyclization of cinnamic acid esters gives
A highly effective cascade process giving 3-alkenylcoumarins is furnished by a series of reactions involving pallada-arylation of ethylpropiolate with phenols, intramolecular transesterification t...
Lewis acid-catalyzed annulative partial dimerization of 3-aryloxyacrylates to 4-arylchroman-2-ones: synthesis of analogues of tolterodine, RORγ inhibitors and a GPR40 agonist
作者:Rupesh A. Kunkalkar、Rodney A. Fernandes
DOI:10.1039/c8cc09785b
日期:——
annulative partial dimerization of 3-aryloxyacrylates to 4-arylchroman-2-ones catalyzed by Lewis acid (BF3·OEt2) has been developed. The reaction involves two molecules of 3-aryloxyacrylate, resulting in the loss of one propiolate molecule to furnish 4-arylchroman-2-one, an important structural motif found in many natural products. This methodology has been elaborated to synthesize analogues of tolterodine
A General Synthetic Route to Dibenzospiropyrans and Dinaphthospiropyrans from Dibenzofuran and Dinaphthofuran
作者:Baiquan Wang、Bin Wang、Minxiong Li、Shansheng Xu、Haibin Song
DOI:10.1055/s-2007-966061
日期:2007.6
The reaction of dibenzofuran or dinaphthofuran with lithium in anhydrous diethyl ether led to a solution of the corresponding C,O-dilithiated intermediate which, upon treatment with 1,3,3-trimethylindolin-2-one or different coumarin derivatives at -78 °C, afforded, after hydrolysis, dibenzospiropyrans and dinaphthospiropyrans in good yields. The structures of all new compounds were determined by single crystal X-ray analysis.