Sodium Butylated Hydroxytoluene: A Functional Group Tolerant, Eco-Friendly Base for Solvent-Free, Pd-Catalysed Amination.
Sodium Butylated Hydroxytoluene: A Functional Group Tolerant, Eco-Friendly Base for Solvent-Free, Pd-Catalysed Amination.
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丁基羟基甲苯钠：一种官能团耐受性、环保型碱，用于无溶剂、钯催化胺化。
作者：
Volodymyr Semeniuchenko;Wilfried M. Braje;M. Organ
NaBHT是一种强但受阻的亲脂性碱，已与类似的亲脂性高反应性Pd-NHC（N-杂环卡宾）催化剂有效配对，以产生用于进行无溶剂（熔融）交叉偶联胺化的理想组合。NaBHT的温和亲核性，加上其共轭酸副产物BHT的抗氧化特性，意味着该工艺似乎没有官能团不相容性。在所有情况下，仅用0.1-0.2摩尔%的催化剂就观察到碱敏感性和氧化还原活性官能团的高效偶联。使用该反应的标准碱KOtBu进行比较，在大多数应用中导致差的偶联或完全降解-只有NaBHT有效。
NaBHT, a strong, but hindered and lipophilic base, has been effectively paired with similarly lipophilic, high-reactivity Pd-NHC (N-heterocyclic carbene) catalysts to produce an ideal combination for performing solvent-free (melt) cross-coupling amination. The mild nucleophilicity of NaBHT, coupled with the anti-oxidant properties of its conjugate acid byproduct, BHT means the process seems to have no functional group incompatibilities. Highly effective coupling of base-sensitive and redox-active functional groups was observed in all cases with only 0.1-0.2 mol percent catalyst. Comparisons using the standard base for this reaction, KOtBu, led to poor couplings or complete degradation in most applications - only NaBHT works.