Steroidal nitro ketones: synthetic and stereochemical aspects

✍ Scribed by Werner Rank

• Book ID: 104225307
• Publisher: Elsevier Science
• Year: 1991
• Tongue: French
• Weight: 201 KB
• Volume: 32
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)92383-9

✦ Synopsis

Various sterordal nmo ketones have been synthesrzed zn a stereocontrolled way by nztratzon of therr respectzve enol acetates with tnfluoroacetyl nitrate (TFAN) Thezr treatment wrth base gave products comparable to

those obtained m base-catalyzed alkyl nitrate nltrah0tt.K Cyclic a-nitro ketones have proven to be useful synthetic intermediates and their synthesis and reactivity have been reviewed by Fischer and Weitzt. The principal synthetic routes to cyclic nitro ketones employ either base-catalyzed alkyl nitrate nitration or acyl nitrate nitration. As far as steroidal nitro ketones are concerned they have been prepared mostly by alkyl nitrate nitration leading in many cases to mixtures of stereo isomers2 and/or nitro enol compounds3. Assuming that in alkyl nitrate mtrations the formation of product mixtures is a result of base-catalyzed epimerization reactions , we subjected enol acetates of sterordal ketones to non-basic acyl nitrate mtrations. We found that under those conditions respective enol acetates were converted to single steroidal nitro ketones in a high-yielding and stereocontrolled way.