The Doubly Base‐Stabilized Diborane(4) [HB(μ‐hpp)]2 (hpp = 1,3,4,6,7,8‐hexahydro‐2H‐pyrimido[1,2‐a]pyrimidinate): Synthesis by Catalytic Dehydrogenation and Reactions with S8 and Disulfides
The Doubly Base‐Stabilized Diborane(4) [HB(μ‐hpp)]2 (hpp = 1,3,4,6,7,8‐hexahydro‐2H‐pyrimido[1,2‐a]pyrimidinate): Synthesis by Catalytic Dehydrogenation and Reactions with S8 and Disulfides
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双碱稳定乙硼烷(4) [HB(μ-hpp)]2 (hpp = 1,3,4,6,7,8-六氢-2H-嘧啶并[1,2-a]嘧啶酸酯)：合成催化脱氢以及与 S8 和二硫化物的反应
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发表时间：
2010
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通讯作者：
Hans‐Jörg Himmel
中科院分区：
文献类型：
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作者：
Nikola Schulenberg;Oxana Ciobanu;E. Kaifer;H. Wadepohl;Hans‐Jörg Himmel
本文报道了在温和条件下催化[h2b (μ-hpp)] 2脱氢生成双碱稳定的二硼烷(4)[HB(μ-hpp)] 2，具有两个hpp桥（hpp = 1,3,4,6,7,8-六氢- 2h -嘧啶[1,2-a]嘧啶酸酯）。对几种脱氢（预）催化剂进行了试验。最好的是Ru 3 (CO) 12，可以在60℃下进行定量脱氢。随后，我们使[HB(μ-hpp)] 2与s8和二硫化物（Ph 2 s2和Bn 2 s2， Bn =苄基）反应。与s8反应后，一个硫原子氧化插入B-B键，生成[HB(μ-hpp)] 2 （μ-S）。在二硫化物的情况下，取代反应导致双碱稳定的二硼烷(4)物种[RSB(μ-hpp)] 2和HB(μ-hpp) 2 BSR （R = Ph或Bn）再次与硫化反应竞争，导致[HB(μ-hpp)] 2 （μ-S）。
In this work we report on new experiments on the catalytic dehydrogenation of [H 2 B(μ-hpp)] 2 leading to the doubly base-stabilized diborane(4) [HB(μ-hpp)] 2 featuring two hpp bridges (hpp = 1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidinate) under mild conditions. Several dehydrogenation (pre)catalysts were tested. The best one turned out to be Ru 3 (CO) 12 , allowing quantitative dehydrogenation already at 60 °C. Subsequently we subjected [HB(μ-hpp)] 2 to reactions with S 8 and disulfides (Ph 2 S 2 and Bn 2 S 2 , Bn = benzyl). Reaction with S 8 leads to oxidative insertion of one sulfur atom into the B―B bond and formation of [HB(μ-hpp)] 2 (μ-S). In the case of disulfides, substitution reactions leading to the doubly base-stabilized diborane(4) species [RSB(μ-hpp)] 2 and HB(μ-hpp) 2 BSR (R = Ph or Bn) compete with sulfuration again leading to [HB(μ-hpp)] 2 (μ-S).