W(CO)<sub>6</sub>-Catalyzed Oxidative Carbonylation of Primary Amines to N,N‘-Disubstituted Ureas in Single or Biphasic Solvent Systems. Optimization and Functional Group Compatibility Studies
作者:Jennifer E. McCusker、A. Denise Main、Kirsten S. Johnson、Cara A. Grasso、Lisa McElwee-White
DOI:10.1021/jo000364+
日期:2000.8.1
Primary amines undergo carbonylation to N,N'-disubstituted ureas using W(CO)(6) as the catalyst, IZ as the oxidant, and CO as the carbonyl source. Preparation of various N,N'-disubstituted ureas from aliphatic primary amines, RNH2 (R = n-Pr, n-Bu, i-Pr, sec-Bu, or t-Bu), was achieved in good to excellent yields. Studies of functional group compatibility using a series of substituted benzylamines demonstrated broad tolerance of functionality during the carbonylation reaction. Preparation of various N,N'-disubstituted ureas from substituted benzylamines, R-C6H4CH2NH2 (R = H, p-OCH3, p-CO2H, p-CO2Et, p-CH2OH, p-SCH3, p-vinyl, p-Cl, p-Br, m-I, p-NH2, p-NO2, or p-CN), was achieved in good yields. For many substituted benzylamines, yields of ureas were higher when a two-phase CH2Cl2/H(2)o solvent system was used.