Highly Efficient Asymmetric Synthesis of Vinylic Amino Alcohols by Zn‐Promoted Benzoyloxyallylation of Chiral N‐tert‐Butanesulfinyl Imines: Facile and Rapid Access to (−)‐Cytoxazone |
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Authors: | Min Liu Xing‐Wen Sun Dr. Ming‐Hua Xu Prof. Dr. Guo‐Qiang Lin Prof. |
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Affiliation: | 1. Key Laboratory of Synthetic Chemistry of Natural Substances, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032 (China), Fax: (+86)?21‐5080‐7388;2. Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zuchongzhi Road, Shanghai 201203 (China) |
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Abstract: | An efficient and convenient α‐hydroxyallylation approach for the asymmetric synthesis of a variety of β‐amino‐α‐vinyl alcohols has been successfully developed. A wide range of vinylic amino alcohol derivatives could be obtained in very good yields and with excellent diastereomeric ratios of up to 99:1 in favor of anti isomers by highly diastereoselective Zn‐promoted benzoyloxyallylation of chiral N‐tert‐butanesulfinyl imines with 3‐bromopropenyl benzoate at room temperature. In particular, excellent enantioinduction of the two new stereogenic centers was observed, with up to 98 % ee. The method provides a new route for the direct α‐hydroxyallylation of imines in a highly stereoselective manner. Moreover, the synthetic value of the method has also been demonstrated by the most concise and straightforward synthesis of (?)‐cytoxazone yet reported. |
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Keywords: | amino alcohols asymmetric synthesis chiral auxiliaries (− )‐cytoxazone hydroxyallylation |
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