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
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
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%).