J. G. Ruano, A. Fraile, M. R. Martín
Dec 10, 1999
Citations
0
Influential Citations
19
Citations
Journal
Tetrahedron
Abstract
Abstract The reactions of tert-butyl (E)-4,4-diethoxy-2-p-tolylsulfinylbut-2-enoate with benzonitrile, acetonitrile, and bromoformonitrile oxides yield isoxazoles. However, (S5,SS)- and (R5,SS)-5-ethoxy-3-p-tolylsulfinylfuranones with benzonitrile oxide afford isoxazolines. The reactivity of the double bond as a dipolarophile is strongly increased by the sulfinyl group. This is also the case of the regioselectivity, which usually is opposite to that exhibited by dipolarophiles lacking the sulfinyl group. Electrostatic interactions seemingly explain this behaviour. The π-facial selectivity of the reactions with the cyclic dipolarophiles is dependent on steric effects, but some role seems to be exerted by electrostatic attraction.