Herein, we report a stereoselective formation of tetrahydro-6H-benzo[e][1,4]oxazino[4,3-a][1,4]diazepine-6,12(11H)-diones. Their preparation consisted in solid-phase synthesis of linear intermediates starting from polymer-supported Ser(tBu)-OH. Using various 2-nitrobenzoic acids and bromoketones, the key intermediates were obtained in five steps and subjected to trifluoroacetic acid-mediated cleavage from the resin, followed by stereoselective reduction with triethylsilane. Subsequent catalytic hydrogenation of the nitro group and cyclization yielded the target compounds with full retention of the C^12a stereocenter configuration.

中文翻译：

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具有两个多样性位置的苯并[ e ] [1,4]恶嗪基[4,3- a ] [1,4]二氮杂-6,12-二酮的立体选择性合成

在此，我们报道了四氢-6 H-苯并[ e ] [1,4]恶嗪基[4,3- a ] [1,4]二氮杂-6,12 （11 H）-二酮的立体选择性形成。他们的制备包括从聚合物负载的Ser（t Bu）-OH开始的线性中间体的固相合成。使用各种2-硝基苯甲酸和溴代酮，可以通过五个步骤获得关键中间体，并从树脂进行三氟乙酸介导的裂解，然后用三乙基硅烷进行立体选择性还原。随后硝基的催化加氢和环化产生具有完全保留的C ^12a立体中心构型的目标化合物。