游离态的一卤硼烷(H_2BX,X=Cl,Br),在通常条件下,缺乏足够的稳定性,不便作为硼氢化试剂。为了克服这一困难,人们通常把它们制成Lewis碱的加成物(H_2BX·L,L=OEt_2,THF,SMe_2)。其中H_2BCl·THF,由于H_2BCl与THF之间的络合作用相当强,故对硼氢化反应表现出惰性。而H_2BCl·OEt,虽然能顺利地使烯烃和炔烃进行硼氢化,得到相应的有机氯硼烷,但其本身只是在溶剂中才具有一定的稳定性,即使在0℃存放数周,也会观察到明显的变化,故使其应用受到了限制。 Free state of a halogen borane (H_2BX, X = Cl, Br), under normal conditions, the lack of sufficient stability, inconvenience as a hydroboration reagent. To overcome this difficulty, they are often made Lewis base adducts (H_2BX · L, L = OEt_2, THF, SMe_2). Among them, H 2 BCl · THF, due to the complexation between H 2 BCl and THF, is rather inert and therefore inert to the hydroboration reaction. H_2BCl · OEt, however, can successfully hydrogenate olefins and alkynes to give the corresponding organochloroborane. However, H_2BCl · OEt itself has only a certain stability in the solvent. Even at 0 ℃ for several weeks, Obvious changes have been observed, so their use has been limited.