1, 2-and 1, 5-stereocontrols in 5-hexenyl radical intramol cyclocondensations: cooperative or antagonist effect. Confrontation of experimental results with MM2 …

…, C Lesueur, S Gastaldi, R Nouguier…

Index: Bertrand, M. P.; Riggi, I. De; Lesueur, C.; Gastaldi, S.; Nouguier, R.; et al. Journal of Organic Chemistry, 1995 , vol. 60, # 19 p. 6040 - 6045

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Citation Number: 20

Abstract

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, ie, exclusive 1, a-truns control, and predominance of 1, Ei-ci. s over 1, 5-truns relationship. The addition of TsBr to carbohydrate-derived epimeric dienes 3a ...