Tetrahedron letters

Reversal of regiochemistry in the synthesis of isoxazoles by nitrile oxide cycloadditions

…, ERT Tiekink, CE Lubin, GP Savage, GW Simpson

Index: Easton; Easton, Christopher J.; Hughes; Merricc Hughes; Tiekink; Tiekink, Edward R. T.; Lubin; Lubin, Carolyn E.; Savage; Paul Savage; Simpson; Simpson, Gregory W. Tetrahedron Letters, 1994 , vol. 35, # 21 p. 3589 - 3592

Full Text: HTML

Citation Number: 36

Abstract

Abstract The isoxazolines 2a, 2b and 8 obtained from nitrile oxide cycloadditions to cyclohex- 2-enone 1a and its analogues 1b and 7 reacted with nickel peroxide to give the isoxazoles 3a, 3b and 9. In contrast, the corresponding 2-bromocyclohex-2-enones 4a, 4b and 10, prepared by bromination of the corresponding alkenes 1a, 1b and 7, underwent nitrile oxide cycloadditions to afford the regioisomeric isoxazoles 6a, 6b and 12, respectively.