Diphenylamino(divinyl)borane (1a) adds two molar equivalents of Piers’ borane [HB(C6F5)2] to give the expected double hydroboration product. In contrast diisopropylamino(divinyl)borane (1b) reacts cleanly already with one molar equivalent of HB(C6F5)2 to give the α-borylated tetrahydroborole derivative 10 in good yield. Subsequent treatment of 10 with benzaldehyde proceeded by retro-hydroboration to give the hydroboration product of the aldehyde plus the dihydroborole 3b. We were able to achieve the divinylborane to dihydroborole isomerization (1b to 3b) catalytically: treatment of diisopropylamino(divinyl)borane (1b) with 15 mol% of Piers’ borane at elevated temperature gave (diisopropylamino)dihydroborole 3b in good yield.
二苯
氨基(二烯)
硼烷(1a)与两个摩尔当量的Piers
硼烷[HB(
C6F5)2]反应,生成预期的双氢
硼化产物。相比之下,
二异丙基氨基(二烯)
硼烷(1b)与一个摩尔当量的HB( )2反应已经很干净,生成α-
硼基化的四氢
硼烯衍
生物10,并且产率良好。随后,对10与
苯甲醛的处理通过逆氢
硼化反应,得到醛的氢
硼化产物及双氢
硼烯3b。我们能够实现二烯
硼烷到双氢
硼烯的异构化(1b到3b),其催化处理为:将
二异丙基氨基(二烯)
硼烷(1b)与15摩尔%的Piers
硼烷在升高温度下反应,良好产率地得到(
二异丙基氨基)双氢
硼烯3b。