A study of regio- and stereo-selectivity in the cycloaddition reactions of a series of symmetrical and unsymmetrical 1,2-disubstituted alkenes to the chiral, internally H-bonded N-(2-hydroxy-1-phenyl)methylenenitrone, has been carried out. The regioselectivity observed in the addition reactions is explained in terms of frontier orbital interactions. The alkenes having a hydroxymethyl substituent at the allylic position are found to undergo regio- as well as highly stereo-selective cycloaddition reactions in the presence of anhydrous magnesium bromide.
研究人员对一系列对称和不对称的 1,2-二取代烯与手性、内部 H 键的 N-(2-羟基-1-苯基)亚甲基腈酮的环加成反应的区域和立体选择性进行了研究。在加成反应中观察到的区域选择性可以用前沿轨道相互作用来解释。研究发现,在无水溴化镁存在下,烯丙基位置上具有羟甲基取代基的烯烃会发生区域和高度立体选择性的环加成反应。