Ni(ClO4)2-catalysed regio- and diastereoselective [3+2] cycloaddition of indoles and aryl oxiranyl-dicarboxylates/diketones: a facile access to furo[3,4-b]indoles
Ni(ClO(4))(2).6H(2)O-catalysed regioselective and diastereoselective [3+2]-annulations of aryl oxiranyl-dicarboxylates and indoles via selective C-C bond cleavage of oxirane were revealed. The cycloadditions proceed smoothly with high regio- and diastereoselectivity under mild conditions leading to 1H-furo[3,4-b]indoles in good to excellent yields.
Divergence of Carbonyl Ylide Reactions as a Function of Diazocarbonyl Compound and Aldehyde Substituent: Dioxolanes, Dioxolenes, and Epoxides
作者:Albert E. Russell、Jonathan Brekan、Luisa Gronenberg、Michael P. Doyle
DOI:10.1021/jo049403y
日期:2004.8.1
The products from dirhodium(II) acetate-catalyzed reactions between diazocarbonyl compounds and a series of benzaldehydes demonstrate the extent of competition between intramolecular and intermolecular trapping of carbonylylide intermediates and the electronic effects that govern these transformations. With dimethyl diazomalonate, competition exists between dioxolane and epoxide formation so that
Synthesis of 2,5-Disubstituted Furans from Sc(OTf)<sub>3</sub> Catalyzed Reaction of Aryl Oxiranediesters with γ-Hydroxyenones
作者:Keshab Mondal、Subhas Chandra Pan
DOI:10.1021/acs.joc.7b00133
日期:2017.4.21
A convenient synthesis of 2,5-disubstitutedfuran was developed by employing donor–acceptor oxiranes in a new reaction with γ-hydroxyenones. Sc(OTf)3 was found to be the best catalyst, and 2,5-disubstitutedfurans are obtained in moderate to good yields under mild reaction conditions. The scope of the reaction is quite decent, allowing for the synthesis of disubstituted furans having aryl and heteroaromatic
Lewis Acid/Rhodium-Catalyzed Formal [3 + 3]-Cycloaddition of Enoldiazoacetates with Donor–Acceptor Cyclopropanes
作者:Qing-Qing Cheng、Yu Qian、Peter Y. Zavalij、Michael P. Doyle
DOI:10.1021/acs.orglett.5b01674
日期:2015.7.17
A formal [8 + 3]-cycloaddition, of enoldiazoacetates with donor acceptor cyclopropanes was realized by the Combination of a Lewis acid-catalyzed diastereoselective [3 + 2]-cycloaddition and a subsequent rhodium-catalyzed chemoselective ring expansion. This tandem transformation provides an efficient approach to highly functionalized cyclohexenes.
Triflic Acid Catalyzed Formal [3 + 2] Cycloaddition of Donor–Acceptor Oxiranes and Nitriles: A Facile Access to 3-Oxazolines
A TfOH-catalyzed chemoselective [3 + 2] cycloaddition of donor-acceptor oxiranes and nitriles is described. This reaction provides an efficient and practical method for the preparation of useful 3-oxazolines in good to excellent yields (up to 99%).