Triphenylphosphine as an effective catalyst for ketoximes addition to acylacetylenes: regio- and stereospecific synthesis of (E)-(O)-2-(acyl)vinylketoximes
作者:Boris A. Trofimov、Tatyana E. Glotova、Marina Yu. Dvorko、Igor’ A. Ushakov、Elena Yu. Schmidt、Al’bina I. Mikhaleva
DOI:10.1016/j.tet.2010.07.057
日期:2010.9
Triphenylphosphine catalyzes the regio- and stereospecific addition of ketoximes to acylacetylenes, whereas classical conditions using acetylene (KOH/DMSO, 70 degrees C) are unsuitable for this purpose. The reaction proceeds under mild conditions (CH2Cl2, rt, 7 h) to afford (E)-(O)-2-(acyl)vinylketoximes (92-98% stereoselectivity) in a yield of up to 85%. The (E)-adducts obtained are energetically less favorable than the corresponding (Z)-isomers and are gradually enriched with (Z)-isomers, thus indicating the kinetic control of (E)-stereoselectivity of the reaction. (C) 2010 Elsevier Ltd. All rights reserved.
Synthesis of О-2-(acyl)vinylketoximes and their unusual rearrangements into 2- and 3-acyl-substituted pyrroles
作者:Tatyana E. Glotova、Elena Yu. Schmidt、Marina Yu. Dvorko、Igor’ A. Ushakov、Al’bina I. Mikhaleva、Boris A. Trofimov
DOI:10.1016/j.tetlet.2010.09.101
日期:2010.11
yields) rearrange upon heating (125–150 °C) to give 2- or 3-acylpyrroles, wherein the positions of the acyl substituents do not correspond to known O-vinyloxime rearrangements; the chemo- and regioselectivity of the rearrangements depend on the reaction conditions. The described rearrangement enables syntheses of previously inaccessible substituted 2- or 3-acylpyrroles.