Aqueous Phosphoric Acid as a Mild Reagent for Deprotection of <i>tert</i>-Butyl Carbamates, Esters, and Ethers
作者:Bryan Li、Martin Berliner、Richard Buzon、Charles K.-F. Chiu、Stephen T. Colgan、Takushi Kaneko、Nandell Keene、William Kissel、Tung Le、Kyle R. Leeman、Brian Marquez、Ronald Morris、Lisa Newell、Silke Wunderwald、Michael Witt、John Weaver、Zhijun Zhang、Zhongli Zhang
DOI:10.1021/jo061377b
日期:2006.11.1
an effective, environmentally benign reagent for the deprotection of tert-butyl carbamates, tert-butyl esters, and tert-butyl ethers. The reaction conditions are mild and offer good selectivity in the presence of other acid-sensitive groups, including CBZ carbamates, azetidine, benzyl and methyl esters, TBDMS, and methyl phenyl ethers. The mildness of the reaction is further demonstrated in the synthesis
磷酸水溶液(85重量%)是用于脱保护的有效,环境友好的试剂叔丁基氨基甲酸酯,叔丁基酯,和叔-丁基醚。反应条件温和,在其他酸敏感基团(包括氨基甲酸CBZ,氮杂环丁烷,苄基和甲基酯,TBDMS和甲基苯基醚)存在下,具有良好的选择性。反应的温和性在克拉霉素衍生物4的合成中得到了进一步证明,其中叔酸在环状氨基甲酸酯,内酯,缩酮,乙酸酯和可差向异构的甲基酮官能团存在下,除去丁酯。该反应保留了底物的立体化学完整性。反应产率高,后处理方便。