Efficient Synthesis of Ureas by Direct Palladium-Catalyzed Oxidative Carbonylation of Amines
作者:Bartolo Gabriele、Giuseppe Salerno、Raffaella Mancuso、Mirco Costa
DOI:10.1021/jo0494634
日期:2004.7.1
A general synthesis of symmetrically disubstituted ureas and trisubstituted ureas by direct Pd-catalyzed oxidative carbonylation of primary amines or of a mixture of a primary and a secondary amine, respectively, with unprecedented catalytic efficiencies for this kind of process, is reported. Reactions are carried out at 90−100 °C in DME as the solvent in the presence of PdI2 in conjunction with an
据报道,通过直接钯催化的伯胺或伯胺和仲胺混合物的直接羰基氧化羰基化,一般合成对称的二取代的脲和三取代的脲,对于这种方法具有空前的催化效率。反应在90-100°C的DME中作为溶剂,在PdI 2的存在下,与过量的KI作为催化体系,在20 atm的CO和空气的4:1混合物下进行。在某些情况下,在过量CO 2的存在下工作除CO和空气(总共60个大气压)外(40个大气压)对底物反应性和产物收率有有益的影响。环状五元和六元尿素很容易由伯二胺形成。该方法已成功地用于合成具有药理活性的尿素,例如那些衍生自α-氨基酯或尿素NPY5RA-972(神经肽Y5受体的强效拮抗剂)的尿素。