Asymmetric Lithiation Trapping of N-Boc Heterocycles at Temperatures above 鈭?8 掳C

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• 作者：Giacomo Gelardi ; Graeme Barker ; Peter O鈥橞rien ; David C. Blakemore
• 刊名：Organic Letters
• 出版年：2013
• 出版时间：November 1, 2013
• 年：2013
• 卷：15
• 期：21
• 页码：5424-5427
• 全文大小：252K
• 年卷期：v.15,no.21(November 1, 2013)
• ISSN：1523-7052

文摘

The asymmetric lithiation trapping of N-Boc heterocycles using s-BuLi/chiral diamines at temperatures up to 鈭?0 掳C is reported. Depending on the N-Boc heterocycle, lithiation is accomplished using s-BuLi and (鈭?-sparteine or the (+)-sparteine surrogate in the temperature range 鈭?0 to 鈭?0 掳C for short reaction times (2鈥?0 min). Subsequent electrophilic trapping or transmetalation鈥揘egishi coupling delivered functionalized N-Boc heterocycles in 47鈥?5% yield and 77:23鈥?3:7 er. With N-Boc pyrrolidine, trapped products can be generated in 90:10 er even at 鈭?0 掳C.