화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.129, No.25, 7720-7720, 2007
Regioselective and enantioselective iridium-catalyzed allylation of enamines
A highly enantioselective and regioselective monoallylation of the enamines of methyl ketones has been developed. After hydrolysis of the enamine (NaOAc/AcOH(aq)), the desired allylated ketones were obtained in high yields (64-91% isolated yields), with high branched-to-linear selectivity (all but two >= 95:5), and with high enantioselectivities (all but two >= 94% ee). The reactions occur within hours at room temperature and encompass the reactions of aromatic and aliphatic methyl ketone derivatives. The enamines of methyl alkyl ketones, which exist as a mixture of two regioisomers, reacted selectively (>= 99:1) at the less hindered position. The use of a preformed cyclometalated iridium catalyst, isopropyl carbonates, toluene solvent, and ZnCl2 as an alcohol adsorbent was important for the development of this process.