Lithium Aminoborohydrides 16. Synthesis and Reactions of Monomeric and Dimeric Aminoboranes
作者:Lubov Pasumansky、Dustin Haddenham、Jacob W. Clary、Gary B. Fisher、Christian T. Goralski、Bakthan Singaram
DOI:10.1021/jo702271c
日期:2008.3.1
coordination. In general aminoboranes are not hydroborating reagents. However, monomeric aminoboranes, such as BH2-N(iPr)2, can reduce nitriles in the presence of catalytic amounts of LiBH4. This BH2-N(iPr)2/LiBH4 reducing system also re-duces ketones, aldehydes, and esters. Diisopropylaminoborane, synthesized from iPr-LAB, can be converted into boronic acids by a palladium-catalyzed reaction with aryl
氨基硼烷是在环境条件下由相应的氨基硼氢化锂(LABs)与甲基碘,三甲基甲硅烷基氯(TMS-Cl)或苄基氯的反应原位合成的。在己烷中,使用甲基碘的反应产生氨基硼烷和甲烷,而在四氢呋喃(THF)中,该反应产生胺-硼烷(R 1 R 2 HN:BH 3)作为主要产物。i Pr-LAB与TMS-Cl或苄基氯的反应仅产生二异丙基氨基硼烷[BH 2 -N(i Pr)2在25°C下在THF中和在己烷中]。由于烷基的空间要求,二异丙基氨基硼烷和二环己基氨基硼烷作为单体存在。研究的所有其他氨基硼烷在空间上均不足以成为溶液中的单体,而是以单体和二聚体的混合物形式存在。二聚体是通过硼-氮配位形成的四元环。通常,氨基硼烷不是硼氢化试剂。但是,单体氨基硼烷,例如BH 2 -N(i Pr)2,可以在催化量的LiBH 4存在下还原腈。该BH 2 -N(i Pr)2 / LiBH 4还原体系还可以还原酮,醛和酯。由i Pr