Highly regioselective Lewis acid-catalyzed [3+2] cycloaddition of alkynes with donor–acceptor oxiranes by selective carbon–carbon bond cleavage of epoxides
Unprecedented Direct Oxygen Atom Transfer from Hypervalent Oxido-λ<sup>3</sup>-iodanes to α,β-Unsaturated Carbonyl Compounds: Synthesis of α,β-Epoxy Carbonyl Compounds
Tetra-n-butylammonium oxido-lambda(3)-iodane, prepared from 1-hydroxy-1,2-benziodoxol-3(1H)-one by reaction with tetra-n-butylammonium fluoride, directly undergoes oxygenatom transfer to alpha,beta-unsaturated carbonylcompounds, yielding epoxides.
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.
Lewis Acid Catalyzed Carbon−Carbon Bond Cleavage of Aryl Oxiranyl Diketones: Synthesis of <i>cis</i>-2,5-Disubstituted 1,3-Dioxolanes
作者:Zuliang Chen、Lai Wei、Junliang Zhang
DOI:10.1021/ol2000292
日期:2011.3.4
Carbonylylide is one of the most important intermediates which can undergo a series of 1,3-dipolar cycloaddition reactions. The C−C heterolysis of oxirane is believed to be the most atom-economic and straightforward way to generate carbonylylide. However, this chemistry was only achieved under photochemical and thermal conditions in past years. In this work, the one-step diastereoselective synthesis
Asymmetric Cycloadditions of Acyclic Carbonyl Ylides with Aldehydes Catalyzed by a Chiral Binaphthyldiimine-Ni(II) Complex: Enantioselective Synthesis of 1,3-Dioxolanes and Mechanistic Studies by DFT Calculations
作者:Yasunori Toda、Kayo Sato、Kensuke Sato、Kazuma Nagasaki、Hirotaka Nakajima、Ayaka Kikuchi、Kimiya Sukegawa、Hiroyuki Suga
DOI:10.1021/acs.orglett.2c01682
日期:2022.7.8
3-dipolar cycloaddition reactions between acyclic carbonyl ylides generated from donor–acceptor oxiranes and aldehydes are reported. Both aromatic and aliphatic aldehydes could be used as dipolarophiles, providing cis-1,3-dioxolanes with high diastereo- and enantioselectivities. On the basis of mechanistic studies, a monomeric chiral Ni(II) complex was hypothesized to act as the active species for the cycloaddition
Nickel-Catalyzed Annulation of Donor-Acceptor Oxiranes with Imines: Diastereoselective Access to Highly Substituted 2,4-<i>trans</i>-Oxazolidines
作者:Junqing Zhang、Yuanjing Xiao、Junliang Zhang
DOI:10.1002/adsc.201300449
日期:2013.10.11
AbstractAn efficient approach for the synthesis of highly substituted 2,4‐trans‐oxazolidines has been achieved by means of nickel(II) chlorate hexahydrate [Ni(ClO4)2⋅6 H2O]‐catalyzed [3+2] dipolar cycloaddition reactions of donor–acceptor oxiranes with imines via CC bond cleavage in good yields with moderate to high diastereoselectivity. The appropriate orientation of two activating ketones or esters is crucial for this chemoselective CC bond cleavage of the oxirane ring.magnified image