Enantioselective Rhodium-Catalyzed [4 + 2] Cycloaddition of α,β-Unsaturated Imines and Isocyanates
摘要:
A [4 + 2] cycloaddition of alpha,beta-unsaturated imines and isocyanates catalyzed by a phosphoramidite rhodium complex provides pyrimidinones in good yields and high enantioselectivities.
Enantioselective Rhodium-Catalyzed [4 + 2] Cycloaddition of α,β-Unsaturated Imines and Isocyanates
作者:Kevin M. Oberg、Tomislav Rovis
DOI:10.1021/ja200766k
日期:2011.4.6
A [4 + 2] cycloaddition of alpha,beta-unsaturated imines and isocyanates catalyzed by a phosphoramidite rhodium complex provides pyrimidinones in good yields and high enantioselectivities.
Facile Synthesis of Chiral Cyclic Ureas through Hydrogenation of 2-Hydroxypyrimidine/Pyrimidin-2(1<i>H</i>
)-one Tautomers
A facileaccess to optically active cyclic ureas was developed through palladium‐catalyzed asymmetric hydrogenation of pyrimidines containing tautomeric hydroxy group with up to 99 % ee. Mechanistic studies indicated that reaction pathway proceed through hydrogenation of C=N of the oxo tautomer pyrimidin‐2(1H)‐one, acid‐catalyzed isomerization of enamine–imine, and hydrogenation of imine pathway. In