Reversal of regiochemistry in the synthesis of isoxazoles by nitrile oxide cycloadditions
作者:Christopher J. Easton、C.Merrîcc Hughes、Edward R.T. Tiekink、Carolyn E. Lubin、G.Paul Savage、Gregory W. Simpson
DOI:10.1016/s0040-4039(00)73248-5
日期:1994.5
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
由对环己-2-烯酮1a的氧化腈环加成反应获得的异恶唑啉2a,2b和8及其类似物1b和7与过氧化镍反应,得到异恶唑3a,3b和9。相反,通过溴化相应的烯烃1a,1b和7制备的相应的2-溴环己基-2-烯酮4a,4b和10经历一氧化氮环加成反应以提供区域异构的异恶唑6a,6b。和12。