Tandem aminopalladation/Suzuki cyclization cascades

描述（由申请人提供）：本提案描述了一个好氧，Pd（ll）催化的串联氨基化/铃木反应的开发和利用。说明了两种不同的策略。一种涉及通过分子内氨基化形成烯丙基钯配合物，而另一种利用氨基化步骤形成中间的pd -烯醇酯。然后，这两种中间体将与系链芳基硼酸发生分子内交叉偶联。虽然交叉偶联事件将导致Pd(0)的产生，但在好氧条件下进行反应将再生所需的Pd(1)催化剂。此外，本建议概述了这种方法在头孢唑胺全合成中的使用；最近发现的一种天然产物亚家族，在结构上与抗白血病的头孢噻嗪酯相关，并已显示出对白血病本身的有效活性。

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.