Synthesis of esters of the potent anti-bacterial trinems and analogues
作者:P. Mark Jackson、Stanley M. Roberts、Silvia Davalli、Daniele Donati、Carla Marchioro、Alcide Perboni、Stefano Proviera、Tino Rossi
DOI:10.1039/p19960002029
日期:——
Coupling the silylenolether 5 and the β-lactam 9(R = Me3Si) affords the ketones 13a–d. Compounds 13a, 13c and 13d are converted into the tricyclic lactams 16–20, 23–25. (Chemoenzymatic synthesis of optically pure silylenolether 5 gave access to homochiral lactams 23–25.) In addition the ketoazetidinones 13 are protected as the 1,3-oxazanes 30. A hydroxyethyl moiety is introduced into these oxazanes
甲硅烷基烯醇醚5和β-内酰胺9(R = Me 3 Si)偶联得到酮13a-d。化合物13a,13c和13d转化为三环内酰胺16-20、23-25。(光学纯的甲硅烷基烯醇醚5的化学酶法合成可得到同手性内酰胺23-25。)此外,酮氮杂环丁酮13被保护为1,3-恶唑烷30。使用Bouffard方法进行所需的立体化学反应,得到醇32。形成相应的碳酸硝基苄酯,脱保护和氧化提供了酮35a和35b,其随后分别转化为三苯甲基41a和41b。
Preparation of Silyl Enol Ethers Using (Bistrimethylsilyl)acetamide in Ionic Liquids
作者:Michael Smietana、Charles Mioskowski
DOI:10.1021/ol015602h
日期:2001.4.1
[reaction: see text]. Ionic liquids have been used for the preparation of silylenolethers from aldehydes and ketones with (bistrimethylsilyl)acetamide (BSA) in good yields.
hydrogenation of racemic 5 using ruthenium-BINAP-diamine-KOH system, followed by oxidation. Magnesium enolate of (2S)-2-methoxycyclohexanone [(S)-5] reacts with the 4-acetoxyazetidinone 4 to give the key intermediate 3 with high yield and diastereoselectivity for the synthesis of sanfetrinem 1.