Recent developments in the metal-catalyzed reactions of metallocarbenoids from propargylic esters
Recent developments in the metal-catalyzed reactions of metallocarbenoids from propargylic esters
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DOI：
10.1002/chem.200601522
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发表时间：
2007-01-01
影响因子：
4.3
通讯作者：
Soriano, Elena
中科院分区：
文献类型：
--
作者：
Marco-Contelles, Jose;Soriano, Elena
过渡金属催化的炔丙基羧酸酯的分子内环异构化以非常非对映选择性的方式提供官能化的双环[n.1.0]烯醇酯，并且根据结构，从对映体纯的前体部分或完全转移手性。随后的甲醇分解得到双环[n.1.0]酮，因此产生了用于合成α，β-不饱和环丙基酮的非常有效的两步方案，α，β-不饱和环丙基酮是制备天然产物的关键中间体。从机械计算研究的结果表明，他们可能会通过环丙基类化合物进行，形成内环丙烷化，经历1，2-酰基迁移。最后，讨论了含侧链芳环的炔丙酯的分子间反应和相关的五环化反应的可能性。
The transition-metal-catalyzed intramolecular cycloisomerization of propargylic carboxylates provides functionalized bicyclo[n.1.0]enol esters in a very diastereoselective manner and, depending on the structure, with partial or complete transfer of chirality from enantiomerically pure precursors. The subsequent methanolysis gives bicyclo[n.1.0] ketones, hence resulting in a very efficient two-step protocol for the syntheses of alpha,beta-unsaturated cyclopropyl ketones, key intermediates for the preparation of natural products. The results from mechanistic computational studies suggest that they probably proceed through cyclopropyl metallocarbenoids, formed by endo-cyclopropanation, that undergo a 1,2-acyl migration. Finally, the potential of the intermolecular reaction and the related pentannulation of propargylic esters bearing pendant aromatic rings are also discussed.