The effect of 4β and 19 ester functionalities on some electrophilic addition reactions of Δ⁵-steroids

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• 作者：Ruddock ; Peter L.D. ; Reese ; Paul B.
• 关键词：Δ ; ⁵-Steroid ; Treibs ; Petrow ; Bromine ; Silver acetate ; Mercury(II) trifluoroacetate
• 刊名：Steroids
• 出版年：1999
• 出版时间：December, 1999
• 年：1999
• 卷：64
• 期：12
• 页码：812-819
• 全文大小：200 K

文摘

The reactions of 3β-acyloxyandrost-5-enes with bromine/silver acetate (Petrow reaction) and mercury(II) trifluoroacetate (modified Treibs oxidation) have been used previously to effect allylic oxidation on these substrates en route to biologically active compounds. In both these reactions, which involve electrophilic addition to the Δ⁵-bond, the 3-acyloxy substituent plays a significant role. In this report, the effect of introducing other substituents proximate to the Δ⁵-bond has been studied by using derivatives of 3β-acetoxyandrost-5-en-17-one (1), namely, 3β,4β-diacetoxyandrost-5-en-17-one (13), 3β,19-diacetoxyandrost-5-en-17-one (14), 3β-acetoxyandrost-5-ene-7,17-dione (15), and 3β-acetoxy-4,4-dimethylandrost-5-en-17-one (17). Our results indicate that in both sets of reactions the effect of the introduced functional groups was pronounced. In the Petrow reaction, electrophilic addition rather than allylic oxidation on the diacetates was observed. With the Treibs reaction, allylic oxidation on the diacetates occurred. The 7-keto and 4,4-dimethyl steroids proved to be poor substrates in both reactions.