ORGN 371 |
| Pd-catalyzed asymmetric allylic alkylation (AAA) has been intensively studied for nearly thirty years. While Pd affords the less substituted, linear allylic products from unsymmetrical allylic electrophiles, most other metals (Rh, Ir, Fe, Mo) provide the more substituted, branched allylic products. Ir-phosphoramidite systems have emerged as excellent catalysts for the allylation of various heteroatom nucleophiles as well as traditional malonate-type carbon nucleophiles. Recently many research groups have been investigating the allylation of non-activated ketones through the usage of silyl enol ethers, enolates, and enol carbonates. One attractive method to achieve ketone allylation is by way of the corresponding enamines. Herein we report that the cyclometallated complex Ir(cod)(κ2-L)(L) (shown in graphic) is a catalyst for the enantioselective allylation of enamines. After hydrolysis of the enamine product, allylated ketones are obtained in high yields and with high branched selectivity and enantioselectivity.
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Asymmetric Reactions and Syntheses
1:00 PM-5:00 PM, Tuesday, March 27, 2007 McCormick Place East -- Room E351, Level 3, Oral
Division of Organic Chemistry |
