Department of Chemistry, Texas A&M University, College Station, TX 77843, USA.
Dalton Trans. 2018 Aug 29;47(34):11843-11850. doi: 10.1039/c8dt00702k.
In the context of our work on electron deficient group 15 cations as Lewis acid catalysts, we have synthesized the triflate salts of a series of tetraarylstibonium cations of general formula [ArSbPh3]+ with Ar = Mes (4+), o-(dimethylamino)phenyl (5+), and o-((dimethylamino)methyl)phenyl (6+). These new cationic antimony derivatives, along with the known [Ph4Sb]+ (1+), 1-naphthyltriphenylstibonium (2+), and [(Ant)SbPh3]+ (3+), have been evaluated as catalysts for the cycloaddition of oxiranes and isocyanates under mild conditions. While all stibonium cations favor the 3,4-oxazolidinone products, the reactivities of 5+ and 6+ are hindered by the ancillary amino donor which quenches the Lewis acidity of the antimony center. A comparison of the other stibonium cations shows that 4+ is the most selective catalyst.
在我们研究缺电子第 15 族阳离子作为路易斯酸催化剂的工作中，我们合成了一系列通式为[ArSbPh3]+的四芳基鏻阳离子的三氟甲磺酸盐，其中 Ar = Mes（4+）、邻-（二甲氨基）苯基（5+）和邻-((二甲氨基)甲基)苯基（6+）。这些新的阳离子锑衍生物，以及已知的[Ph4Sb]+（1+）、1-萘基三苯基鏻（2+）和[(Ant)SbPh3]+（3+），已被评估为在温和条件下环氧化合物和异氰酸酯加成反应的催化剂。虽然所有的鏻阳离子都有利于生成 3,4-恶唑烷酮产物，但 5+和 6+的反应性受到辅助氨基供体的阻碍，该供体猝灭了锑中心的路易斯酸度。对其他鏻阳离子的比较表明，4+是最具选择性的催化剂。
