Reaction of 2,3-dimethyl-1,3-butadiene with chiral (E)-2-cyanocinnamates

  1. Avenoza, A. 1
  2. Cativiela, C.
  3. Mayoral, J.A. 2
  4. Peregrina, J.M. 1
  1. 1 Universidad de La Rioja
    info

    Universidad de La Rioja

    Logroño, España

    ROR https://ror.org/0553yr311

  2. 2 Instituto de Nanociencia y Materiales de Aragón
    info

    Instituto de Nanociencia y Materiales de Aragón

    Zaragoza, España

    ROR https://ror.org/031n2c920

Revista:
Tetrahedron: Asymmetry

ISSN: 0957-4166

Año de publicación: 1992

Volumen: 3

Número: 7

Páginas: 913-919

Tipo: Artículo

DOI: 10.1016/S0957-4166(00)82189-8 SCOPUS: 2-s2.0-0026692879 WoS: WOS:A1992JD93700016 GOOGLE SCHOLAR

Otras publicaciones en: Tetrahedron: Asymmetry

Resumen

The reactions of 2,3-dimethyl-1,3-butadiene with (E)-2-cyanocinnamates of (S)-ethyl lactate (1a) and (R)-pantolactone (1b), catalysed by TiCl4, afford enantiomerically pure cycloadducts which are easily converted into the enantiomers (1R, 6S) and (1S, 6R) of the methyl 1-cyano-3,4-dimethyl-6-phenyl-3-cyclohexen-1-carboxylate. The reactions with TiCl4 can be explained by the dienophile-TiCl4 chelate model proposed by Helmchen. The non-catalysed reaction of (1b) with the same diene takes place at 100°C, with a moderately high d.e. and reversal of selectivity.