Regioselective and Enantioselective Iridium-Catalyzed Allylation of Enamines
2007; American Chemical Society; Volume: 129; Issue: 25 Linguagem: Inglês
10.1021/ja071455s
ISSN1943-2984
AutoresDaniel J. Weix, John F. Hartwig,
Tópico(s)Synthetic Organic Chemistry Methods
ResumoA 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.
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