KU Leuven, Department of Chemistry, Molecular Design and Synthesis, Celestijnenlaan 200F - box 2404, B-3001 Leuven, Belgium.
Org Biomol Chem. 2021 Jul 14;19(26):5782-5787. doi: 10.1039/d1ob00728a. Epub 2021 May 11.
An efficient, scalable and sustainable method for the quantitative deprotection of the tert-butyl carbamate (N-Boc) protecting group is described, using down to near-stoichiometric amounts of hydrogen chloride gas in solvent-free conditions. We demonstrate the ex situ generation of hydrogen chloride gas from sodium chloride and sulfuric acid in a two-chamber reactor, introducing a straightforward method for controlled and stoichiometric release of HCl gas. The solvent-free conditions allow deprotection of a wide variety of N-Boc derivatives to obtain the hydrochloride salts in quantitative yields. The procedure obviates the need for any work-up or purification steps providing an uncomplicated green alternative to standard methods. Due to the solvent-free, anhydrous conditions, this method shows high tolerance towards acid sensitive functional groups and furnishes expanded functional group orthogonality.
描述了一种高效、可扩展且可持续的定量脱保护叔丁基氨基甲酸酯（N-Boc）保护基的方法，在无溶剂条件下使用低至近化学计量的氯化氢气体。我们证明了在双室反应器中从氯化钠和硫酸原位生成氯化氢气体，引入了一种用于控制和化学计量释放 HCl 气体的简便方法。无溶剂条件允许脱保护各种 N-Boc 衍生物，以定量产率获得盐酸盐。该方法避免了任何后处理或纯化步骤的需要，为标准方法提供了一种简单的绿色替代方案。由于无溶剂、无水条件，该方法对酸敏感官能团具有高耐受性，并提供了扩展的官能团正交性。
