RESUMO
Chiral pyrimidines with a fluorine atom in the benzylic position are easily accessible in high enantiomeric excesses from optically active propargylic intermediates by two complementary routes. Both the use of optically active propargylic fluorides and the fluorination of the chiral pyrimidine in the final stage give excellent results in terms of enantiocontrol. On the other hand, original pyrimidines with a difluoromethyl side chain are also obtained in a few steps from new propargylic ketones bearing a CHF(2) substituent on the triple bond.
Assuntos
Hidrocarbonetos Fluorados/síntese química , Pirimidinas/síntese química , Alcinos/química , Bromobenzenos/síntese química , Bromobenzenos/química , Hidrocarbonetos Fluorados/química , Cetonas/químicaRESUMO
A new cooperative copper/iron catalysis for the borylation of various aryl bromides with pinacolborane, at -10 °C, is reported. Use of the toxic, precious metal Pd is avoided. The mechanism of the protodebromination side reaction is discussed.