937722-58-2Relevant academic research and scientific papers
Asymmetric homoaldol reactions with cyclohex-2-enyl N,N- diisopropylcarbamate: Kinetic resolution, elucidation of the stereochemical course and applications in the synthesis of hexahydroisobenzofuran-4-(1H)-ones
Becker, Jochen,Froehlich, Roland,Salorinne, Kirsi,Hoppe, Dieter
, p. 3337 - 3348 (2007)
Enantio-enriched cyclohex-2-enyl N,N-diisopropylcarbamate (5) is stereospecifically deprotonated by sec-butyllithium/(-)-sparteine (9) to form the configurationally stable lithium complex 7.9. A kinetic resolution of rac-5 by n-butyllithium/(-)-sparteine (9) yielded (R)-5 with up to 99 % ee. Electrophilic substitution with tin electrophiles proceeds in a anti-S E′ fashion as shown by chemical correlations. The synthesized allylstannanes 10 undergo a highly stereospecific TiCl4-mediated homoaldol reaction with various aldehydes, yielding syn-configured homoaldol products 12. These were transferred into all-cis-configured hexahydroisobenzofuran-4(1H)-ones 22 by BF3·OEt 2-mediated reactions with aldehydes. The configurations of several products were determined by X-ray structure analysis. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Estimation of the kinetic acidity from substrate conformation - Stereochemical course of the deprotonation of cyclohexenyl carbamates
Becker, Jochen,Grimme, Stefan,Froehlich, Roland,Hoppe, Dieter
, p. 1645 - 1649 (2008/03/12)
Get the bends: The kinetic C-H acidity of cyclohex-2-enyl carbamates is dependent on the torsion angle between the α C-H bond and the π system of the adjacent double bond. A deprotonation study and DFT calculations of the activation energies for lithiatio
