Kinetic Resolution by Lithiation: Highly Enantioselective Synthesis of Substituted Dihydrobenzoxazines and Tetrahydroquinoxalines
Kinetic Resolution by Lithiation: Highly Enantioselective Synthesis of Substituted Dihydrobenzoxazines and Tetrahydroquinoxalines
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DOI：
10.1055/a-1638-2478
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发表时间：
2021-09-06
影响因子：
2.6
通讯作者：
Coldham, Iain
中科院分区：
文献类型：
--
作者：
El-Tunsi, Ashraf;Carter, Nicholas;Coldham, Iain
动力学拆分提供了一种使用正丁基锂和手性配体斯巴豆碱来合成3-芳基-3，4-二氢-2H-1，4-苯并恶嗪的高对映选择性方法。在去除叔丁氧基(Boc)保护基团的过程中，对映体保持较高的富集度。中间体有机锂与烯胺发生开环反应。将动力学拆分扩展到对映体富集型取代的1，2，3，4-四氢喹恶啉，并将其应用于抗生素左氧氟沙星类似物的合成，筛选了其对人体致病菌肺炎链球菌的活性。
Kinetic resolution provided a highly enantioselective method to access a range of 3-aryl-3,4-dihydro-2H-1,4-benzoxazines using n-butyllithium and the chiral ligand sparteine. The enantioenrichment remained high on removing the tert-butoxycarbonyl (Boc) protecting group. The intermediate organolithium undergoes ring opening to an enamine. The kinetic resolution was extended to give enantiomerically enriched substituted 1,2,3,4-tetrahydroquinoxalines and was applied to the synthesis of an analogue of the antibiotic levofloxacin that was screened for its activity against the human pathogen Streptococcus pneumoniae.