Indium(III) Halides as New and Highly Efficient Catalysts for <i>N</i>-<i>tert</i>-Butoxycarbonylation of Amines
作者:Asit Chakraborti、Sunay Chankeshwara
DOI:10.1055/s-2006-942492
日期:2006.8
Indium(III) bromide and chloride efficiently catalysed the N-tert-butoxycarbonylation of amines with (Boc)2O at room temperature and under solvent-free conditions. Various aromatic, heteroaromatic and aliphatic amines were converted to N-tert-butylcarbamates in excellent yields in short times. Chiral amines, esters of α-amino acids and β-amino alcohols afforded optically pure N-t-Boc derivatives in high yields. The reactions were chemoselective and no competitive side reactions such as isocyanate, urea, and N,N-di-t-Boc formation were observed. Chemoselective conversion to N-tert-butylcarbamates took place with amino alcohols without any formation of oxazolidinones.
溴化铟(III)和氯化铟(III)在室温下以及无溶剂条件下有效地催化胺类与(Boc)2O的N-叔丁氧羰基化反应。多种芳香、杂芳香和脂肪胺类在短时间内高效转化为N-叔丁基氨基甲酸酯。手性胺、α-氨基酸酯和β-氨基醇在较高产率下得到光学纯的N-t-Boc衍生物。反应具有化学选择性,未观察到异氰酸酯、脲和N,N-二-t-Boc形成等竞争性副反应。氨基醇也能进行化学选择性转化为N-叔丁基氨基甲酸酯,而不形成噁唑烷酮。