Difluoramination of Heterocyclic Ketones: Control of Microbasicity
Difluoramination of Heterocyclic Ketones: Control of Microbasicity
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DOI：
10.1021/jo9718399
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发表时间：
1998-02
影响因子：
3.6
通讯作者：
R. Chapman;Mark F. Welker;Charles B. Kreutzberger
中科院分区：
文献类型：
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作者：
R. Chapman;Mark F. Welker;Charles B. Kreutzberger
通过选择适当的保护基，使四氢-1，5-二氮杂环辛四烯-3，7（2 H，6 H）-二酮二氟胺化为相应的3，3，7，7-四（二氟氨基）二氮杂环辛四烯。在用二氟氨基磺酸缓慢破坏9-氧杂-3，7-二氮杂双环[3.3.1]壬烷中间体中的跨环桥的过程中，证明了用于二氮杂环辛四烯氮的芳烃磺酰基保护基上级乙酰基。虽然1，5-二甲苯磺酰基衍生物不能进行超过二氟胺与一个酮羰基加成的产物（半缩醛胺6），但使用4-硝基苯磺酰基作为保护基将二酮和中间体中的氮的碱性降低到低于氧位点的碱性，使得反应进行到偕-双（二氟氨基）二氮杂环辛四烯产物（11）。描述了一种更安全的处理二氟胺的方法。
Difluoramination of a tetrahydro-1,5-diazocine-3,7(2H,6H)-dione to the corresponding 3,3,7,7-tetrakis(difluoramino)diazocine was achieved by a judicious choice of protecting group. Arenesulfonyl protecting groups for the diazocine nitrogens proved superior to acetyl during the slow disruption of the transannular bridge in 9-oxa-3,7-diazabicyclo[3.3.1]nonane intermediates by difluorosulfamic acid. While a 1,5-ditosyl derivative failed to proceed beyond the product of addition of difluoramine to one ketone carbonyl (hemiaminal 6), the use of 4-nitrobenzenesulfonyl as the protecting groups lowered the nitrogens' basicities below that of the oxygen site in the dione and intermediates, allowing the reaction to proceed to a gem-bis(difluoramino)diazocine product (11). A safer procedure for handling difluoramine is described.