Reduction of amine N-oxides by diboron reagents.
Reduction of amine N-oxides by diboron reagents.
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DOI：
10.1021/jo201192c
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发表时间：
2011-10-07
影响因子：
3.6
通讯作者：
Lakshman, Mahesh K.
中科院分区：
文献类型：
--
作者：
Kokatla, Hari Prasad;Thomson, Paul F.;Bae, Suyeal;Doddi, Venkata Ramana;Lakshman, Mahesh K.
烷基胺-、苯胺-和吡啶- n -氧化物的简单还原可以通过使用二硼试剂来实现，主要是双（pinacolato）和在某些情况下双（儿茶酚ato）二硼[分别为（pinB）2和（catB）2]。还原发生在简单的混合胺n -氧化物和二硼试剂在适当的溶剂，在适当的温度。烷基胺和苯胺- n -氧化物的还原速度极快，而吡啶- n -氧化物的还原速度较慢。该反应可耐受各种官能团，如羟基、巯基、氰基以及卤素。值得注意的是，一个敏感的核苷n -氧化物也被有效地还原了。利用烷基胺和吡啶-N-氧化物的不同还原速率，对(S)-(-)-烟碱的N，N ' -二氧化物进行了分步还原。由于观察到（pinB）2不受胺氧化物水化水的影响，因此评价了以水为溶剂的可行性。这些反应也进行得非常好，产物收率很高。与（pinB）2反应相比，三乙基硼烷还原烷基胺- n -氧化物，而吡啶- n -氧化物即使在高温下也不能进行有效的还原。最后，通过1H和11B NMR对（pinB）2还原过程的机理进行了探讨。
Facile reduction of alkylamino-, anilino-, and pyridyl-N-oxides can be achieved via the use of diboron reagents, predominantly bis(pinacolato)- and in some cases bis(catecholato)diboron [(pinB)2 and (catB)2, respectively]. Reductions occur upon simply mixing the amine N-oxide and the diboron reagent in a suitable solvent, at a suitable temperature. Extremely fast reductions of alkylamino- and anilino-N-oxides occur, whereas pyridyl-N-oxides undergo slower reduction. The reaction is tolerant of a variety of functionalities such as hydroxyl, thiol, and cyano groups, as well as halogens. Notably, a sensitive nucleoside N-oxide has also been reduced efficiently. The different rates with which alkylamino- and pyridyl-N-oxides are reduced has been used to perform stepwise reduction of the N,N’-dioxide of (S)-(–)-nicotine. Because it was observed that (pinB)2 was unaffected by the water of hydration in amine oxides, the feasibility of using water as solvent was evaluated. These reactions also proceeded exceptionally well, giving high product yields. In constrast to the reactions with (pinB)2, triethylborane reduced alkylamino-N-oxides, but pyridine N-oxide did not undergo efficient reduction even at elevated temperature. Finally, the mechanism of the reductive process by (pinB)2 has been probed by 1H and 11B NMR.
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影响因子：
1.8
作者：
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通讯作者：
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影响因子：
3.6
作者：
Bae, Suyeal;Lakshman, Mahesh K.
通讯作者：
Lakshman, Mahesh K.