Stereoselective formation of optically active 2-oxy-1,3-oxazolidin-4-ones from chiral O-acylmandelamides or lactamides
作者:Akio Kamimura、Yoji Omata、Akikazu Kakehi、Masashi Shirai
DOI:10.1016/s0040-4020(02)01057-8
日期:2002.10
(-)-O-Acyllactamides or mandelamides in the presence of TBSOTf underwent cyclization reaction to give optically active 2-oxy-1,3-oxazolidin-4-ones, a novel nitrogen analog of orthoesters, in good yields. An X-ray analysis and NOE studies indicated that the absolute configuration at the newly formed chiral carbon was S. For their synthetic application, the 1,3-dipolar cycloaddition of nitrile oxide was examined. The cycloadducts were obtained in a stereoselective manner. Subsequent treatment of the adduct with TBAF resulted in the one-step removal of mandelamide, giving optically active 4,5-dihydroisoxazole and mandelamide in good yields. (C) 2002 Elsevier Science Ltd. All rights reserved.
(-)-O-Acyllactamides 或 mandelamides 在 TBSOTf 存在下发生环化反应,生成具有光学活性的 2-oxy-1,3-oxazolidin-4-ones(一种新型氮类似物),产率良好。X 射线分析和 NOE 研究表明,新形成手性碳的绝对构型为 S。在合成应用方面,研究了硝基氧化物的 1,3-偶极环加成反应。环加成产物以立体选择性方式获得。随后,用 TBAF 处理加成物,一步去除了 mandelamide,生成具有光学活性的 4,5-dihydroisoxazole 和 mandelamide,产率良好。 (C) 2002 Elsevier Science Ltd. 保留所有权利。