AbstractReactions of 5‐SIDipp ⋅ BH3 (5‐SIDipp=1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene) (1) with diphenyldiselenide provide access to 5‐SIDipp–boryl mono‐ (5‐SIDipp ⋅ BH2SePh) (2) and bis‐selenide (5‐SIDipp ⋅ BH(SePh)2) (3). The facile cleavage of the B−Se bond makes 2 a neutral source of selenium nucleophiles in substitutions reactions with benzyl bromides, and provide access to the corresponding selenoethers. The direct transformations of one of the C(sp2)−F bonds of C5F5N and C6F5CF3 to C−Se bonds have also been achieved by the use of 2 without employing transition‐metal catalysts. While it was previously established that C6F6 could undergo complete defluoroselenation under harsh conditions, we successfully achieved partial defluorination of C6F6 by employing 2 as a mild selenide transfer reagent. During the formation of C−Se bonds through the cleavage of C−F bonds, the potential by‐product NHC ⋅ BH2F undergoes ring expansion of the NHC, leading to the formation of the six‐membered diaazafluoroborinane (7).
摘要5-SIDipp⋅
BH3(5-SIDipp=
1,3-双(
2,6-二异丙基苯基)-
咪唑啉-2-亚基)(1)与二
苯基二
硒化物的反应提供了 5-SIDipp-
硼酰单(5-SIDipp⋅BH2SePh)(2)和双
硒化物(5-SIDipp⋅BH(SePh)2)(3)的途径。B-Se 键的简易裂解使 2 成为
苄基溴取代反应中
硒亲核的中性来源,并提供了获得相应
硒醚的途径。使用 2 还可以将
C5F5N 和 C6F5CF3 的一个 C(sp2)-F 键直接转化为 C-Se 键,而无需使用过渡
金属
催化剂。虽然之前已经证实
C6F6 可以在苛刻条件下发生完全
脱氟硒化反应,但我们通过使用 2 作为温和的
硒化转移试剂,成功地实现了 的部分
脱氟化反应。在通过裂解 C-F 键形成 C-Se 键的过程中,潜在的副产物 NHC⋅BH2F 会发生 NHC 的环扩张,从而形成六元重
氮氟硼烷 (7)。