Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467 (USA).
Angew Chem Int Ed Engl. 2014 Feb 10;53(7):1968-72. doi: 10.1002/anie.201309430. Epub 2014 Jan 29.
A broadly applicable Ru-catalyzed protocol for Z-selective ring-opening/cross-metathesis (ROCM) is disclosed. In addition to reactions relating to terminal alkenes of different sizes, the first examples of Z-selective ROCM processes involving heteroaryl olefins, 1,3-dienes, and O- and S-substituted alkenes as well as allylic and homoallylic alcohols are reported. Z-Selective transformations with an α-substituted allylic alcohol are shown to afford congested Z alkenes with high diastereoselectivity. Transformations are performed in the presence of 2.0-5.0 mol % of a recently disclosed Ru-based dithiolate complex that can be easily prepared in a single step from commercially available starting materials. Typically, transformations proceed at ambient temperature and are complete within eight hours; products are obtained in up to 97 % yield, >98:2 Z/E, and >98:2 diastereomeric ratio. The present investigations reveal a mechanistically significant attribute of the Ru-based dithiolates that arises from electrostatic interactions with anionic S-based ligands.
本文公开了一种普适性的 Ru 催化的 Z 选择性开环/交叉复分解（ROCM）反应。除了涉及不同大小的末端烯烃的反应外，本文还首次报道了 Z 选择性 ROCM 过程中涉及杂芳基烯烃、1,3-二烯、O 和 S 取代的烯烃以及烯丙基和偕烯丙基醇的例子。具有α取代的烯丙醇的 Z-选择性转化被证明可以高非对映选择性地得到稠合的 Z 烯烃。反应是在 2.0-5.0 mol%的最近公开的基于 Ru 的二硫代配合物存在下进行的，该配合物可以很容易地从商业上可获得的起始原料一步制备得到。通常，反应在环境温度下进行，在八小时内完成；产物的收率高达 97%，Z/E 比值大于 98:2，非对映选择性比值大于 98:2。目前的研究揭示了基于 Ru 的二硫代配合物的一个在机理上很重要的特性，这是由于与阴离子 S 基配体的静电相互作用而产生的。
