1,2-Azaboratabenzene: A Heterocyclic π-Ligand with an Adjustable Basicity at Nitrogen

1,2-Dihydro-2-phenyl-1,2-azaborine (6a) has been prepared by a multistep synthesis from the readily available 2,2-dibutyl-2,5-dihydro-1-trimethylsilyl-1H-1,2-azastannole (7). Deprotonation of 6a affords 1-phenyl-1,2-azaboratabenzene 1a, which on reaction with [Cp*RuCl]4 gives the sandwich compound 5. 5 has been shown to function as a nucleophilic catalyst for the acylation of benzyl alcohol by phenylethylketene.1,2-二氢-2-苯基-1,2-氮杂硼杂苯(6a)可由易得的2,2-二丁基-2,5-二氢-1-三甲基硅基-1H-1,2-氮杂锡杂环戊二烯(7)经多步合成制备。对6a进行去质子化处理，可得到1-苯基-1,2-氮杂硼杂苯阴离子(1a)；该阴离子与[Cp*RuCl]4反应后生成夹心化合物5。研究表明，化合物5可作为亲核催化剂，用于催化苯甲醇与苯乙基烯酮的酰化反应。