Understanding the Unusual Regioselectivity in the Nucleophilic Ring-Opening Reactions of gem-Disubstituted Cyclic Sulfates. Experimental and Theoretical Studies

  1. Avenoza, A. 1
  2. Busto, J.H. 1
  3. Corzana, F. 1
  4. García, J.I. 2
  5. 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

Aldizkaria:
Journal of Organic Chemistry

ISSN: 0022-3263

Argitalpen urtea: 2003

Alea: 68

Zenbakia: 11

Orrialdeak: 4506-4513

Mota: Artikulua

DOI: 10.1021/JO034178Q SCOPUS: 2-s2.0-0037764769 WoS: WOS:000183066100047 GOOGLE SCHOLAR

Beste argitalpen batzuk: Journal of Organic Chemistry

Gordailu instituzionala: lock_openSarbide irekia Editor

Laburpena

The regioselectivity of the nucleophilic ring-opening reactions of three gem-disubstituted cyclic sulfates with sodium azide has been studied from both experimental and theoretical viewpoints. It is found that, depending on the substituent present in the cyclic sulfate, the reaction displays reversed regioselectivity, which allows one or another regioisomer to be obtained with selectivities greater than 4:1. The theoretical calculations show that, contrary to previous understanding, the intrinsic preference in all cases is azide attack at the less-substituted Cβ position, a consequence of similar stereoelectronic effects in the three sulfates considered. The observed preference for Cα attack in the case of the ester sulfate is explained in terms of differential solvent effects, which are in turn due to subtle differences in the charge transfer in the different transition structures.