Synthesis and the thermal and catalytic dehydrogenation reactions of amine-thioboranes.
Synthesis and the thermal and catalytic dehydrogenation reactions of amine-thioboranes.
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DOI：
10.1021/ic3008188
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发表时间：
2012-07
影响因子：
4.6
通讯作者：
A. Robertson;M. Haddow;I. Manners
中科院分区：
文献类型：
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作者：
A. Robertson;M. Haddow;I. Manners
合成并表征了一系列三甲基胺-硫代硼烷加合物Me（3）N·BH（2）SR（R = tBu [2a]，nBu [2b]，iPr [2c]，Ph [2d]，C（6）F（5）[2 e]）。尝试通过涉及这些物种的胺交换反应获得硫代硼烷的仲胺和伯胺加合物被证明是不成功的，硫醇盐部分被证明容易被游离胺置换。然而，用Me（2）NH和iPr（2）NH处理芳基硫代硼烷[BH（2）-SPh]（3）（9）和C（6）F（5）SBH（2）·SMe（2）（10），成功地得到了加合物Me（2）NH·BH（2）SR（R = Ph [11a]，C（6）F（5）[12a]）和iPr（2）NH·BH（2）SR（R = Ph [11b]，C（6）F（5）[12b]）。这些加合物还显示可通过热诱导的氨基硼烷Me（2）N BH（2）（分别衍生自环状二聚体[Me（2）N-BH（2）]（2）（13）和iPr（2）N BH（2）（14））的氢硫醇化来获得。然而，通过该方法制备脂肪族硫醇盐取代的加合物R（2）NH·BH（2）SR'（R = Me，iPr; R' = tBu，nBu，iPr）的尝试被证明是不成功的，促进氢硫醇化所需的温度也诱导胺-硫代硼烷产物热脱氢形成氨基硫代硼烷，R（2）N·BH（SR '）。还研究了目标胺-硫代硼烷11 a/11b和12 a/12 b的热脱氢和催化脱氢。加合物11b和12 b在100 °C（18小时，甲苯）下干净地脱氢，分别得到iPr（2）N·BH（SPh）（22）和iPr（2）N·BH（SC（6）F（5））（23），在前一种物质的情况下，也可以在20 °C（42小时，甲苯）下用2摩尔%负载的[Rh（μ-Cl）cod]（2）脱氢。对加合物11 a的类似研究证明了在热处理时H（2）和HSPh的竞争性消除，以及在催化条件下的其他复杂反应性，而发现氟化类似物12 a对脱氢具有抗性。
A series of trimethylamine-thioborane adducts, Me(3)N·BH(2)SR (R = tBu [2a], nBu [2b], iPr [2c], Ph [2d], C(6)F(5) [2e]) have been prepared and characterized. Attempts to access secondary and primary amine adducts of thioboranes via amine-exchange reactions involving these species proved unsuccessful, with the thiolate moiety shown to be vulnerable to displacement by free amine. However, treatment of the arylthioboranes, [BH(2)-SPh](3) (9) and C(6)F(5)SBH(2)·SMe(2) (10) with Me(2)NH and iPr(2)NH successfully yielded the adducts Me(2)NH·BH(2)SR (R = Ph [11a], C(6)F(5) [12a]) and iPr(2)NH·BH(2)SR (R = Ph [11b], C(6)F(5) [12b]) in high yield. These adducts were also shown to be accessible via thermally induced hydrothiolation of the aminoboranes Me(2)N═BH(2), derived from the cyclic dimer [Me(2)N-BH(2)](2) (13), and iPr(2)N═BH(2) (14), respectively. Attempts to prepare the aliphatic thiolate substituted adducts R(2)NH·BH(2)SR' (R = Me, iPr; R' = tBu, nBu, iPr) via this method, however, proved unsuccessful, with the temperatures required to facilitate hydrothiolation also inducing thermal dehydrogenation of the amine-thioborane products to form aminothioboranes, R(2)N═BH(SR'). Thermal and catalytic dehydrogenation of the targeted amine-thioboranes, 11a/11b and 12a/12b were also investigated. Adducts 11b and 12b were cleanly dehydrogenated to yield iPr(2)N═BH(SPh) (22) and iPr(2)N═BH(SC(6)F(5)) (23), respectively, at 100 °C (18 h, toluene), with dehydrogenation also possible at 20 °C (42 h, toluene) with a 2 mol % loading of [Rh(μ-Cl)cod](2) in the case of the former species. Similar studies with adduct 11a evidenced a competitive elimination of H(2) and HSPh upon thermolysis, and other complex reactivity under catalytic conditions, whereas the fluorinated analogue 12a was found to be resistant to dehydrogenation.