Diastereo- and Enantioselective Synthesis of (E)-2-Methyl-1,2-syn- and (E)-2-Methyl-1,2-anti-3-pentenediols via Allenylboronate Kinetic Resolution with (d

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• 作者：Jeng-Liang Han ; Ming Chen ; William R. Roush
• 刊名：Organic Letters
• 出版年：2012
• 出版时间：June 15, 2012
• 年：2012
• 卷：14
• 期：12
• 页码：3028-3031
• 全文大小：283K
• 年卷期：v.14,no.12(June 15, 2012)
• ISSN：1523-7052

文摘

Enantioselective hydroboration of racemic allenylboronate (卤)-1 with 0.48 equiv of (^dIpc)₂BH at 鈭?5 掳C proceeds with efficient kinetic resolution and provides allylborane (R)-Z-4. When heated to 95 掳C, allylborane (R)-Z-4 isomerizes to the thermodynamically more stable allylborane isomer (S)-E-7. Subsequent allylboration of aldehydes with (R)-Z-4 or (S)-E-7 at 鈭?8 掳C followed by oxidative workup provides 1,2-syn- or 1,2-anti-diols, 2 or 3, respectively, in 87鈥?4% ee.