The nuclear magnetic resonance spectra of representative 5-nitro-6-substituted-2-norbornenes (II–VII) are described. From the spectra, ratios of the two possible endo–exo trans stereoisomers derived from the Diels–Alder reaction of cyclopentadiene with the appropriate trans nitroolefin are estimated as shown in Table II. For all cases, there was predominance (3:1 to 9:1) of the 5-endo-nitro trans stereoisomer
描述了代表性 5-硝基-6-取代-2-
降冰片烯 (II-VII) 的核磁共振谱。根据光谱,从
环戊二烯与合适的反式硝基烯烃的 Diels-Alder 反应衍生的两种可能的内-外反式立体异构体的比例估计如表 II 所示。对于所有情况,5-内-硝基反式立体异构体占优势(3:1 至 9:1)。报道了 6-(对
硝基苯基) (V)、6-(2-
呋喃基) (VI) 和 6-(2-
噻吩基) (VII) 衍
生物的合成,6-乙基衍
生物 (III) 具有被表征