Reactivity of chiral exocyclic N-acyliminium ions with aromatic derivatives

✍ Scribed by Tiziana Mecozzi; Marino Petrini; Roberto Profeta

• Book ID: 104359726
• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 301 KB
• Volume: 14
• Category: Article
• ISSN: 0957-4166
• DOI: 10.1016/s0957-4166(03)00123-x

✦ Synopsis

Chiral N-acyliminium ions obtained from optically active N- [1-(phenylsulfonyl)alkyl]oxazolidin-2-ones at low temperature in the presence of titanium tetrachloride react with electron-rich aromatic compounds to afford the corresponding adducts in good yields and variable diastereoselectivities. Chemoselective cleavage of the oxazolidin-2-one ring with lithium/ammonia affords the corresponding benzylamines in enantioenriched form. The utilization of 4-benzyloxazolidin-2-one as a chiral auxiliary leads to intramolecular cyclization with exclusive formation of one diastereomer. The obtained tricyclic derivatives possess the core structure of some aza analogs of the anticancer drug podophyllotoxin.