TY - JOUR
T1 - 1,2- and 1,5-Stereocontrols in 5-Hexenyl Radical Cyclizations: Cooperative or Antagonist Effect. Confrontation of Experimental Results with MM2 Calculations of Transition States
AU - Bertrand, M. P.
AU - De Riggi, I.
AU - Lesueur, C.
AU - Gastaldi, S.
AU - Nouguier, R.
AU - Jaime, C.
AU - Virgili, A.
PY - 1995/9/1
Y1 - 1995/9/1
N2 - The cyclofunctionalization of 1,6-dienes 1 and 2 via the addition of tosyl radical allows the analysis of the combined effects of 1,2- and 1,5-stereocontrols on the outcome of 5-hexenyl radical cyclizations. MM2 calculations of transition states agree quite well with the experimental selectivity, i.e., exclusive 1,2-trans control, and predominance of 1,5-cis over 1,5-trans relationship. The addition of TsBr to carbohydrate-derived epimeric dienes 3a and 3b shows that the stereochemistry of the newly formed C—C bond is controlled by the configuration of the C2 center of the radical. 1,5-trans or 1,5-cis selectivity can be achieved depending on the configuration of C2. © 1995, American Chemical Society. All rights reserved.
AB - The cyclofunctionalization of 1,6-dienes 1 and 2 via the addition of tosyl radical allows the analysis of the combined effects of 1,2- and 1,5-stereocontrols on the outcome of 5-hexenyl radical cyclizations. MM2 calculations of transition states agree quite well with the experimental selectivity, i.e., exclusive 1,2-trans control, and predominance of 1,5-cis over 1,5-trans relationship. The addition of TsBr to carbohydrate-derived epimeric dienes 3a and 3b shows that the stereochemistry of the newly formed C—C bond is controlled by the configuration of the C2 center of the radical. 1,5-trans or 1,5-cis selectivity can be achieved depending on the configuration of C2. © 1995, American Chemical Society. All rights reserved.
U2 - 10.1021/jo00124a012
DO - 10.1021/jo00124a012
M3 - Article
VL - 60
SP - 6040
EP - 6045
IS - 19
ER -