Synthesis of 3-Oxazolines via SnCl4-Promoted Formal [3+2] Cycloaddition of Donor–Acceptor Oxiranes and Nitriles
作者:Xiaofei Zeng、Guofu Zhong、Hai Zhou、Yan Xie
DOI:10.1055/s-0034-1380216
日期:——
A novel SnCl4-promoted formal [3+2] cycloaddition of donor–acceptor oxiranes and nitrilesvia chemoselective C–C bond breakage was developed. This reaction provides an efficient and practical method for the preparation of 3-oxazolines in good yields (up to 89%).
CO Versus CC Bond Cleavage: Selectivity Control in Lewis Acid Catalyzed Chemodivergent Cycloadditions of Aryl Oxiranyldicarboxylates with Aldehydes, and Theoretical Rationalizations of Reaction Pathways
A clean break: Lewisacidcatalyzedchemodivergent [3+2] cycloadditions of aryloxiranyldicarboxylates with aldehydes are revealed, in which the CC or CObondcleavage of oxiranes can be controlled by the use of Ni(ClO4)2 or Sn(OTf)2 catalysts (see scheme). Possible reactionpathways for these transformations are demonstrated by theoretical calculations.
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.
Reaction of Two Differently Functionalized Oxiranes with Nickel Perchlorate: A Modular Entry to Highly Substituted 1,3-Dioxolanes
作者:Zuliang Chen、Yuanjing Xiao、Junliang Zhang
DOI:10.1002/ejoc.201300558
日期:2013.8
Nickelperchlorate catalyzed sequential Meinwald rearrangement of a terminal oxirane through C–O bond cleavage, and cycloaddition with a donor–acceptor oxirane through C–C bond cleavage was developed. The same catalyst mediates the ring opening of the oxirane moiety in twodifferent ways. This method provides an alternative route to synthesize highlysubstituted1,3-dioxolanes by using oxiranes instead
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