Tandem aminopalladation/Suzuki cyclization cascades

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DESCRIPTION (provided by applicant): This proposal describes the development and utilization of an aerobic, Pd(ll)-catalyzed tandem aminopalladation/Suzuki reaction. Two different strategies are illustrated. One involves the formation of an allylpalladium complex via an intramolecular aminopalladation, while the other utilizes the aminopalladation step to form an intermediate Pd-enolate. Both of these intermediates will then undergo an intramolecular cross-coupling with a tethered aryl boronic acid. While the cross-coupling event will result in the production of a Pd(0) species, conducting the reaction under aerobic conditions will regenerate the required Pd(ll) catalyst. In addition, this proposal outlines the use of this methodology in the total synthesis of the cephalezomines; a recently discovered subfamily of natural products that are structurally related to the antileukemic cephalotaxine esters, and have shown potent activity against leukemia themselves.