Silver(I)-Catalyzed Aminocyclization of 2,3-Butadienyl and 3,4-Pentadienyl Carbamates: An Efficient and Stereoselective Synthesis of 4-Vinyl-2-oxazolidinones and 4-Vinyltetrahydro-2<i>H</i>-1,3-oxazin-2-ones
作者:Masanari Kimura、Shuji Tanaka、Yoshinao Tamaru
DOI:10.1246/bcsj.68.1689
日期:1995.6
Silver(I) salts in combination with an appropriate base (mostly triethylamine) catalyzed the aminocyclization of N-substituted 2,3-butadienyl carbamates 1 (benzene, 50 °C) to provide 4-vinyl-2-oxazolidinones 2 in good yields. The stereoselectivity (trans-2/cis-2) ranged from 1.4 for C5-Me to >30 for C5-phenyl, isopropenyl, and t-butyl derivatives. 3,4-Pentadienyl tosylcarbamates 3, the one-carbon higher homologues of 1, underwent a similar cyclization to give 4-vinyltetrahydro-2H-1,3-oxazin-2-one 4 in synthetically useful yields and in higher trans selectivities than 1.
银(I)盐与适当的碱(主要是三乙胺)催化N-取代的2,3-丁二烯基氨基甲酸酯1(苯,50°C)进行环化反应,以良好产率得到4-乙烯基-2-恶唑啉酮2。立体选择性(反式2/顺式2)从C5-甲基的1.4到C5-苯基、异丙烯基和叔丁基衍生物的>30不等。3,4-戊二烯基对甲苯磺酰氨基甲酸酯3,作为1的碳数多一的同系物,经历了类似的环化反应,以合成上有用的产率得到4-乙烯基四氢-2H-1,3-恶嗪-2-酮4,并且其反式选择性高于1。