已经合成了2个α-和2个β-甲基和甲氧基-5α-胆甾烷-3-酮和3个α-和3个β-甲基-和甲氧基5α-胆甾烷-2-酮,并且它们的变温圆二色性获得并分析光谱。α轴和赤道CH3和OCH3基团的旋转强度(R)值是通过与母体酮的差异测量来确定的。(小)赤道CH3 R值未始终遵循八分法则。轴向OCH3基团不遵守Octant规则(“抗octant”行为),并在C = O n-pi过渡上施加红移。赤道OCH3组并非始终遵循八进制或“反八进制”行为。
Reactions of thallium(I) carboxylates and iodine with alkenes
作者:Richard C. Cambie、Rodney C. Hayward、John L. Roberts、Peter S. Rutledge
DOI:10.1039/p19740001858
日期:——
Treatment of an alkene with a thallium(I) carboxylate and iodine gives the corresponding vic-iodocarboxylate in high yield. The reactions are regiospecific and in conjunction with solvolysis of the products, offer an alternative to the Prévost reaction. Differences in the behaviour of thallium(I) carboxylates and silver carboxylates towards alkenes in the presence of iodine are discussed.
The reaction of the following steroidal olefins with iodine–copper(II) acetate in acetic acid afforded the corresponding steroidal trans-iodo acetates: 5α-cholest-1-, -2-, and -3-ene; and 5β-cholest-1-, -2-, and -3-ene.