Convenient Synthesis of 4-Methylene-2-oxazolidinones and 4-Methylenetetrahydro-1,3-oxazin-2-ones via Transition-Metal Catalyzed Intramolecular Addition of Nitrogen Atom to Acetylenic Triple Bond
作者:Yoshinao Tamaru、Masanari Kimura、Shuji Tanaka、Sigeru Kure、Zen-ichi Yoshida
DOI:10.1246/bcsj.67.2838
日期:1994.10
2-Propynyl tosylcarbamates 1 undergo cyclization smoothly by the catalysis of CuCl/Et3N or AgNCO/Et3N to furnish 4-methylene-2-oxazolidinones 2 in good yields. The similar cyclization of the N-acyl derivatives of 1 (PhCO, MeCO, EtOCO, etc.) is catalyzed effectively by AgNCO/t-BuOK. These reactions accommodate a variety of substituents at C1 and C3 of 2-propyn-1-ol and provide (Z)-2 as single stereoisomers. The scope of the cyclization of 3-butynyl carbamates is rather limited, and in general only N-tosyl derivatives of terminally unsubstituted 3-butyn-1-ols undergo cyclization to give 4-methylenetetrahydro-1,3-oxazin-2-ones in synthetically useful yields by the catalysis of AgNCO/Et3N or AgNCO/t-BuOK.
2-丙炔基甲苯磺酰氨基甲酸酯1在CuCl/Et3N或AgNCO/Et3N的催化下顺利进行环化反应,以良好的产率得到4-亚甲基-2-恶唑烷酮2。1的N-酰基衍生物(PhCO,MeCO,EtOCO等)在AgNCO/t-BuOK的催化下也能有效地进行类似的环化反应。这些反应在2-丙炔-1-醇的C1和C3位上容纳了多种取代基,并提供了(Z)-2作为单一立体异构体。3-丁炔基氨基甲酸酯的环化反应范围相当有限,通常只有末端未取代的3-丁炔-1-醇的N-甲苯磺酰基衍生物在AgNCO/Et3N或AgNCO/t-BuOK的催化下进行环化反应,以合成上有用的产率得到4-亚甲基四氢-1,3-氧杂环壬-2-酮。