Synthesis of hindered chiral guanidine bases starting from (S)-(N,N-dialkyl-aminomethyl)pyrrolidines and BrCN
摘要:
An efficient method for the preparation of hindered chiral quanidines using cyanogen bromide is described. The reaction between BrCN and vicinal diamines derived from (S)-2-(N,N-dialkyl-amiilomethyl)-pyrrolidines provides chiral substituted cyanamides. The cyanamide derivatives reacted with secondary amines in hexafluoroisopropanol at reflux to form chiral hindered guanidines, which were isolated in good to excellent yields (70-96%). The chiral guanidines were prepared in an effort to design sophisticated chiral guanidine catalysts for asymmetric synthesis. (c) 2006 Elsevier Ltd. All rights reserved.
Synthesis of hindered chiral guanidine bases starting from (S)-(N,N-dialkyl-aminomethyl)pyrrolidines and BrCN
摘要:
An efficient method for the preparation of hindered chiral quanidines using cyanogen bromide is described. The reaction between BrCN and vicinal diamines derived from (S)-2-(N,N-dialkyl-amiilomethyl)-pyrrolidines provides chiral substituted cyanamides. The cyanamide derivatives reacted with secondary amines in hexafluoroisopropanol at reflux to form chiral hindered guanidines, which were isolated in good to excellent yields (70-96%). The chiral guanidines were prepared in an effort to design sophisticated chiral guanidine catalysts for asymmetric synthesis. (c) 2006 Elsevier Ltd. All rights reserved.