A. Benavides et al., Synthesis and cycloaddition reactions of new captodative olefins N-substituted 5-alkylidene-1,3-oxazolidine-2,4-diones, HETEROCYCLE, 55(3), 2001, pp. 469-485
An efficient and straightforward synthesis of the new captodative olefins N
-substituted 5-alkylidene-1,3-oxazolidine-2,4-diones (8-10) is described, b
y a chemoselective oxidative cleavage of the novel exo-2-oxazolidinone dien
es (3, 4, and 7), respectively. A study of the reactivity and selectivity o
f olefins (8-10), was carried out in Diels-Alder cycloadditions to cyclic a
nd unsymmetric acyclic olefins. In all reactions, the corresponding adducts
were obtained in high stereo- and regioselectivity. These results have bee
n rationalized in terms of FMO theory by ab initio calculations. 1,3-Dipola
r additions of nitrones to olefin (8a) were also highly regioselective, yie
lding only the C-5 substituted adducts.