Halo- and azidodediazoniation of arenediazonium tetrafluoroborates with trimethylsilyl halides and trimethylsilyl azide and sandmeyer-type bromodediazoniation with Cu(I)Br in [BMIM][PF6] ionic liquid
Halo- and azidodediazoniation of arenediazonium tetrafluoroborates with trimethylsilyl halides and trimethylsilyl azide and sandmeyer-type bromodediazoniation with Cu(I)Br in [BMIM][PF6] ionic liquid
复制标题
DOI：
10.1021/jo701937e
复制
发表时间：
2008-01-04
影响因子：
3.6
通讯作者：
Laali, Kenneth K.
中科院分区：
文献类型：
--
作者：
Hubbard, Abigail;Okazaki, Takao;Laali, Kenneth K.
固定在[BMIM][PF 6]离子液体（IL）中的[ArN 2][BF 4]盐与TMSX（X = 1，Br）和TMSN 3的反应代表了通过脱重氮制备碘-，溴-和叠氮基衍生物的有效方法。该反应也可以从ArNH 2开始，通过用[NO][BF 4]原位重氮化，然后与TMSX或TMSN 3反应来进行。根据取代基上的重氮苯阳离子，竞争氟脱重氮（ArF形成）和加氢脱重氮（ArH形成）进行了观察。脱重氮与TMSN 3和TMSI一般给最高的化学选择性对ArN 3和ArI的形成。IL被回收并重复使用多达5次，转化率没有明显降低。[ArN 2][BF 4]/TMSX、[BMIM][PF 6]/TMSX和[BMIM][PF 6]/TMSX/[ArN 2][BF 4]相互作用的多核NMR监测表明，TMSF主要通过[ArN 2][BF 4]/TMSX形成，原位生成[ArN 2][X]，其在脱重氮化时得到ArX。在Sandmeyer型[ArN 2][BF 4]溴化脱重氮反应中，ArF与固定在IL中的Cu（I）Br竞争形成，表明异解脱重氮反应显著参与。
[GRAPHICS]Reaction of [ArN2][BF4] salts immobilized in [BMIM][PF6] ionic liquid (IL) with TMSX (X = 1, Br) and TMSN3 represents an efficient method for the preparation of iodo-, bromo-, and azido-derivatives via dediazoniation. The reactions can also be effected starting with ArNH2 by in situ diazotization with [NO][BF4] followed by reaction with TMSX or TMSN3. Depending on the substituents on the benzenediazonium cation, competing fluorodediazoniation (ArF formation) and hydrodediazoniation (ArH formation) were observed. Dediazoniation with TMSN3 and with TMSI generally gave the highest chemoselectivity toward ArN3 and ArI formation. The IL was recycled and reused up to 5 times with no appreciable decrease in the conversions. Multinuclear NMR monitoring of the interaction of [ArN2][BF4]/TMSX, [BMIM][PF6]/TMSX, and [BMIM][PF6]/TMSX/[ArN2][BF4] indicated that TMSF is formed primarily via [ArN2][BF4]/TMSX, generating [ArN2][X] in situ, which gives ArX on dediazoniation. Competing formation of ArF in Sandmeyer-type bromodediazoniation of [ArN2][BF4] with Cu(I)Br immobilized in the IL points to significant involvement of heterolytic dediazoniation.