Intramolecular Metal-Catalyzed Alkene (2+2}Cycloaddition

描述：(申请人提供)尽管有大量关于金属催化的环加成反应的研究，但到目前为止，还没有关于金属的报道 分子内烯烃(2，2)环加成反应催化剂。我们在此描述 第一个用于分子内环丁烷化的金属催化剂。这种方法论 可方便地组装双环(3.2.0)正庚烷环系统。相关的光化学过程通常表现出较差的立体选择性和 由于激发态的猝灭，对于非环底物是无效的 通过烯烃异构化。相比之下，我们的烯烃金属催化剂 (2)环加成反应对非环前体物是可行的，并且所有的环加成产物都是 以单一立体异构体的形式获得。这一方法将被用于 波波烷和司帕烷家族成员的一般合成方法 天然产品。Spatane家族的某些成员强烈地抑制细胞 人黑色素瘤和224C星形细胞瘤细胞系的分裂。斯帕托尔‘s 抗有丝分裂活性归因于抑制微管组装。 最后，开发该化合物的对映选择性变体的策略 方法论概述。

DESCRIPTION: (provided by applicant) Despite a wealth of research pertaining to metal catalyzed cycloadditions, to date, there are no reports of metal catalysts for intramolecular alkene (2+2)cycloaddition. We herewith describe the first metal catalyst for intramolecular cyclobutanation. This methodology allows for facile assembly of bicyclo(3.2.0)heptane ring systems. Related photochemical processes generally exhibit poor levels of stereoselectivity and are inefficient for acyclic substrates due to quenching of the excited state via alkene isomerization. In contrast, our metal catalyst for alkene (2+2)cycloaddition is viable for acyclic precursors and all cycloadducts are obtained as single stereoisomers. This methodology will be utilized in a general synthetic approach to members of the bourbonane and spatane families of natural products. Certain members of the spatane family strongly inhibit cell division in human melanoma and 224C astrocytoma neoplastic cell lines. Spatol's antimitotic activity is attributed to inhibition of microtubule assembly. Finally, strategies for development of enantioselective variants of this methodology are outlined.