Whilst the reaction of Δ5, 6-steroids with the mixture Pb-IV-acetate -4(CH3)3SiN3 yields the 7α-azidosteroids at room temperature an opening of the rings A and B in the given steroids 1–6 takes place at the diminished temperature of −15° to the corresponding 5,6-seco-5-oxo-6-oic-nitrile compounds of the steroids. Likewise an analogous splitting results, if the 3-methyl-Δ2 cholestene (7) is treated
Cheap, readily available, air stable, nontoxic, and environmentally benign iron salts such as Fe(acac)3 are excellent precatalysts for the cross-coupling of Grignardreagents with alkenyl triflates and acid chlorides. Moreover, it is shown that dichloroarene and -heteroarene derivatives as the substrates can be selectively monoalkylated by this method. All cross-coupling reactions proceed very rapidly
廉价,容易获得,空气稳定,无毒且对环境无害的铁盐,例如Fe(acac)3是格氏试剂与链烯基三氟甲磺酸酯和酰氯交叉偶联的出色的预催化剂。此外,显示出通过该方法可以将作为底物的二氯亚芳基和-杂亚芳基衍生物选择性地单烷基化。所有交叉偶联反应在特别温和的条件下均能非常快速地进行,结果证明与两个反应伙伴中的各种官能团均相容。对制备结果的详细分析表明,铁催化的碳键形成可以通过不同的途径发生。因此,甲基卤化镁的反应可能包含铁酸盐配合物作为活性成分,而格氏试剂与两个或多个碳原子的反应则受到形式组成[Fe(MgX)2 ]的高度还原的铁簇的影响。n原位生成。使用复杂的[Me 4 Fe] Li 2的对照实验证实了这一解释。
Hageman,H.J.; Havinga,E., Recueil des Travaux Chimiques des Pays-Bas, 1969, vol. 88, p. 97 - 109