Stereocontrol in Radical Cyclization: Change in Rate-Determining Step

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• 作者：Siddiki S. M. A. Hakim ; Takashi Sugimura
• 刊名：Organic Letters
• 出版年：2010
• 出版时间：August 20, 2010
• 年：2010
• 卷：12
• 期：16
• 页码：3626-3629
• 全文大小：190K
• 年卷期：v.12,no.16(August 20, 2010)
• ISSN：1523-7052

文摘

Intramolecular cyclization of an α-carbon radical of ester carrying a chiral 2,4-pentanediol tether shows low stereoselectivity when the radical carbon has an alkyl substituent, while the selectivity becomes high to give a single stereoisomer (>99% pure) when the substituent is an aryl group. The difference in the selectivity is attributable to the change in the rate-determining step from the conformational process to the cyclization.