硝酮与螺［5．5］－1－十一烯－3－酮的环加成反应

CYCLOADDITION OF NITRONES TO SPIRO [5.5]UNDEC-1 -EN-3-ONE

（Ｚ）－Ｎ一苯基－α－取代苯基硝酮与螺［５．５］－１－十一烯－３－酮的环加成反应，制得一种新的杂螺环及几个螺取代的异唑衍生物，经核磁谱确定只有一种区域选择异构体，两种几何异构体．并对３ｂ进行了ｘ－衍射结构分析，进一步证实了其立体构型．

A new heterocycle-system and several spiro-substituted isoxazole derivatives were synthesized by 1, 3-dipolar cycloadditions of (Z)-N-phenyl-a-substituted-pheny nitrones to spiro [5. 5]undec-1-en-3-one. NMR studies confirmed that only one regioisomer and two geometrical i-someres were formed selectively. X-ray structure analysis carried out for one 3b of these products shows the occurrence of only one stereoismer.