Alkali metal reduction of 2-halogeno- and 2-thiolato-2,3-dihydro-1H-1,3,2-diazaboroles
作者:Lothar Weber、Markus Schnieder、Peter Lönnecke
DOI:10.1039/b106128n
日期:2001.12.3
The reduction of 2-bromo-1,3,2-diazaborole tBuNCHCH(tBu)BBr (4c) with a potassium mirror in 1,2-dimethoxyethane afforded a non-separable 1 ∶ 2 ∶ 1 mixture of the compounds tBuNCHCHN(tBu)BH (5), tBuNCHCHN(tBu)BOCH3 (6) and tBuNCHCHN(tBu)B}2O (7). Reaction of 4c with a potassium–sodium alloy in N,N,N′,N′-tetramethylethylenediamine led to 5 as the major product. 1,3,2-Diazaboroles tBuNCHCHN(tBu)BNMe2
(8) and tBuNCHCHN(tBu)B}2 (9) were spectroscopically identified as minor products. The treatment of 4c with potassium–sodium alloy in toluene solution in the presence of [15]crown-5 yielded a 1 ∶ 1 mixture of 5 and the benzyl derivative tBuNCHCHN(tBu)BCH2Ph (12). The same reaction in toluene-d8 produced the deuterated species 5-d1 and 12-d7. tBuNCHCHN(tBu)BCH3 (17) and 1,4-diazabutadiene (tBuNCH)2
(18) resulted from the treatment of tBuNCHCHN(tBu)BSCH3 (15) with potassium–sodium alloy in n-hexane. In contrast to this, compound 9 was obtained as the main product of the reduction of tBuNCHCHN(tBu)BStBu (16) under similar conditions. The reduction of the 1-bromo-2-tert-butyl-1,2-dihydro[1,3,2]diazaborolo[1,5-a]pyridine (19) smoothly produced the respective diborane(4) derivative (20) which was subjected to X-ray diffraction analysis.
将2-溴-1,3,2-二氮硼烷tBuNCHCH(tBu)BBr (4c)在1,2-二甲氧基乙烷中用钾镜还原,得到了一个不可分离的1∶2∶1混合物,包含化合物tBuNCHCHN(tBu)BH (5)、tBuNCHCHN(tBu)BOCH3 (6)和tBuNCHCHN(tBu)B}2O (7)。将4c与钾-钠合金在N,N,N′,N′-四甲基乙二胺中反应,主要产物为5。1,3,2-二氮硼烷tBuNCHCHN(tBu)BNMe2 (8)和tBuNCHCHN(tBu)B}2 (9)被光谱学鉴定为次要产物。用钾-钠合金在存在[15]冠-5的甲苯溶液中处理4c,得到了5和苄基衍生物tBuNCHCHN(tBu)BCH2Ph (12)的1∶1混合物。在甲苯-d8中的相同反应产生了去uterated物种5-d1和12-d7。将tBuNCHCHN(tBu)BSCH3 (15)用钾-钠合金在正己烷中处理,得到了tBuNCHCHN(tBu)BCH3 (17)和1,4-二氮丁二烯(tBuNCH)2 (18)。与此相对,在相似条件下,化合物9是tBuNCHCHN(tBu)BStBu (16)还原的主要产物。1-溴-2-叔丁基-1,2-二氢[1,3,2]二氮硼烷[1,5-a]吡啶(19)的还原顺利产生了相应的二硼烷(4)衍生物(20),并进行了X射线衍射分析。