The high syn selectivity (e.g., synlanti ⩾ 83:17) observed in epoxidation of the torsionally and sterically unbiased 5,6-cis,exo-disubstitutedbicyclo[2.2.2]oct-2-enes (bearing electron withdrawing groups) progressively decreases on going to dihydroxylation and 1,3-dipolar cycloadditions, with practically no selectivity in the case of nitrones and dominance of anti attack in the reactions of diazomethane
在扭转和空间无偏的5,6-顺式,外-双取代双环[2.2.2]辛-2-烯(带有吸电子基团)的环氧化中观察到的高顺式选择性(例如,synlanti⩾83:17)逐渐降低与二羟
甲烷和1,3-偶极环加成反应相比,在硝酮的情况下几乎没有选择性,而在
重氮甲烷的反应中反攻占支配地位(西兰提32:68),这与基于Cieplak理论的预测相反。