115095-74-4Relevant academic research and scientific papers
α-Acylamino Radical Cyclizations: Application to the Synthesis of a Tetracyclic Substructure of Gelsemine
Choi, Joong-Kwon,Ha, Deok-Chan,Hart, David J.,Lee, Chih-Shone,Ramesh, Subban,Wu, Shung
, p. 279 - 290 (2007/10/02)
Syntheses of gelsemine substructures 2 and 3 are described.Free-radical precursors 14,18,35 and 38 were prepared, and their behavior upon treatment with tri-n-butyltin hydride and AIBN was examined.The radical derived from 14 afforded reduction product 15, whereas the radicals derived from 18,35, and 38 gave cyclization products 23,37, and 39, respectively.Aspects of these free-radical cyclizations as well as the conversion of 23 and 37 to 2 and 3, respectively, are presented.
Synthetic Studies toward Gelsemine. 2. Preparation of the Tetracyclic Skeletal Part by Way of a Highly Stereospecific Intramolecular Reaction of a Silyl Enol Ether with an N-Acyliminium Ion
Hiemstra, Henk,Vijn, Robert Jan,Speckamp, W. Nico
, p. 3882 - 3884 (2007/10/02)
The tetracyclic skeletal part of the oxindole alkaloid gelsemine (1) was prepared from (E)-3,5-hexadien-1-ol in nine steps, including as the key step an unprecedented stereospecific cyclization reaction of a triisopropylsilyl enol ether with an N-acyliminium ion intermediate to give a tricyclic aldehyde (3 -> 4).
SYNTHEIEC STUDIES TOWARDS GELSEMINE , I. THE IMPORTANCE OF THE ANTIPERIPLANAR EFFECT IN THE HIGHLY REGIOSELECTIVE REDUCTION OF NON-SYMMETRICAL CIS-HEXAHYDROPHTHALIMIDES.
Vijn, Robert J.,Hiemstra, Henk,Kok, Joost J.,Knotter, Martin,Speckamp, W. Nico
, p. 5019 - 5030 (2007/10/02)
During studies aimed at the total synthesis of gelsemine an exceptional example of regioselectivity has been discovered. cis-Hexahydrophthalimides, which are non-symmetrical through the presence of the one alkyl group (see Figure 1), are reduced by sodium borohydride into the corresponding hydroxy lactams with very high regioselectivity.The corresponding cis-tetrahydrophthalimides exhibit much lower selectivity.These findings are explained on the basis of the conformational preference of the imide molecule and the antiperiplanar effect.
