Rh(III)-catalyzed [5+1] oxidative cycloaddition of arylguanidines with alkynes: a novel access to C4-disubstituted 1,4-dihydroquinazolin-2-amines.
A novel and mild Rh(III)-catalyzed [5+1] oxidative cycloaddition between arylguanidines and alkynes efficiently affords C4-disubstituted 1,4-dihydroquinazolin-2-amines. Members of this family of heterocycles, which contain the relevant cyclic guanidine units, have shown interesting pharmacological properties. The mechanism probably involves the formation of an eight-membered rhodacycle in which the imine unit of guanidine is coordinated to the Rh center. This rhodacycle would evolve to give the C-4 disubstituted 1,4-dihydroquinazolin-2-amine skeleton.
Departamento de Química Orgánica y Centro Singular de Investigación en Química Biológica y Materiales Moleculares (CIQUS), Universidad de Santiago de Compostela, 15782 Santiago de Compostela, Spain. carlos.saa@usc.es.
Ana
A
Cajaraville
Jaime
J
Suárez
Susana
S
López
Jesús A
JA
Varela
Carlos
C
Saá
D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D061565:Cycloaddition Reaction; D006146:Guanidines / Q000737:chemistry*; D008956:Models, Chemical; D011799:Quinazolines / Q000138:chemical synthesis*; D012428:Ruthenium / Q000737:chemistry*
D000480:Alkynes; D006146:Guanidines; D011799:Quinazolines; D012428:Ruthenium