Tandem aminopalladation/Suzuki cyclization cascades

描述(由申请人提供)：本提案描述了好氧、Pd(11)催化的串联氨基转移/铃木反应的开发和应用。文中介绍了两种不同的策略。一种是通过分子内氨基配位形成烯丙基钯配合物，另一种是通过氨基配位形成中间体Pd-烯酸酯。然后，这两个中间体都将与被系留的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)物种的产生，但在好氧条件下进行反应将再生所需的Pd(11)催化剂。此外，这项建议概述了在头孢唑胺的全合成中使用这一方法，头孢唑胺是最近发现的天然产物的一个亚家族，在结构上与抗白血病的头孢他汀酯相关，并显示出强大的抗白血病活性。

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.