The Cyclic Voltammetry and Cathodic Reduction of Steroidal Homoallylic Nitro Esters. Dimerization<i>vs.</i>Cyclopropane Formation
作者:Takeo Sato、Yoshihisa Komeichi、Shoichi Kobayashi、Aira Omura
DOI:10.1246/bcsj.55.520
日期:1982.2
The cathodic reduction of homoallylic nitro esters was carried out in DMF–TBAP using platinum electrodes. The reaction was found to be highly dependent on the ester-leaving group: Whereas 6-nitrocholest-5-en-3β-yl acetate (3a) gave a 3,3′-dimer 4, 3β-tosylate 3d gave a cyclosteroid, 6β-nitro-3α,5-cyclo-5α-cholestane (7). 3β-Trifluoroacetate showed intermediate behavior and gave both 4 and 7. Similarly, 6-nitrocholest-5-ene-3β,19-diol 3-acetate 19-tosylate gave 5β,19-cyclosteroid. The cyclic voltammetry was carried out for these and related compounds. A reversible cyclic voltammogram was recorded for 3a, but 3d showed no anodic peak on potential reversal. A possible electron-transfer and the following chemical-reaction mechanism was discussed.
在DMF-TBAP中使用铂电极进行了同烯丙基硝基酯的阴极还原反应。发现该反应高度依赖于酯离去基团:6-硝基胆甾-5-烯-3β-基乙酸酯(3a)生成3,3'-二聚体4,而3β-对甲苯磺酸酯3d生成甾体环合物,即6β-硝基-3α,5-环-5α-胆甾烷(7)。3β-三氟乙酸酯表现出中间行为,同时生成4和7。类似地,6-硝基胆甾-5-烯-3β,19-二醇3-乙酸酯19-对甲苯磺酸酯生成5β,19-环甾体。对这些化合物及其相关化合物进行了循环伏安法分析。记录了3a的可逆循环伏安图,但3d在电位反转时未显示阳极峰。讨论了可能的电子转移和随后的化学反应机制。