All-carbon tetrasubstituted olefins have been found in numerous biologically important compounds and organic materials. However, regio- and stereocontrolled construction of this structural motif still constitutes a significant synthetic challenge. Here, we show that a modular and regioselective synthesis of all-carbon tetrasubstituted olefins can be realized via alkenyl halide- or triflate-mediated palladium/norbornene catalysis, which is enabled by a modified norbornene containing a C2 amide moiety. This new norbornene co-catalyst effectively suppressed undesired cyclopropanation pathways, which have previously been a main obstacle for developing such reactions. Diverse cyclic and acyclic alkenyl bromides or triflates with a wide range of functional groups can be employed as substrates. Various substituents can be introduced at the alkene C1 and C2 positions regioselectively simply by changing the coupling partners. Initial mechanistic studies provide insights on the rate-limiting step as well as the structure of the actual active ligand in this system.

中文翻译：

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烯基Cathellani反应可实现全碳四取代烯烃的模块化和区域选择性合成。

全碳四取代的烯烃已发现在许多生物学上重要的化合物和有机材料中。然而，该结构基序的区域和立体控制构造仍然构成了重大的合成挑战。在这里，我们表明可以通过链烯基卤化物或三氟甲磺酸盐介导的钯/降冰片烯催化来实现全碳四取代烯烃的模块化和区域选择性合成，这可以通过含有C2酰胺基团的改性降冰片烯来实现。这种新的降冰片烯助催化剂可有效抑制不希望的环丙烷化途径，而这以前是发展此类反应的主要障碍。具有广泛官能团范围的不同的环状和无环链烯基溴化物或三氟甲磺酸酯可用作底物。可以简单地通过改变偶联配偶体而在区域上将C 1和C 2位置选择性地引入各种取代基。最初的力学研究提供了关于限速步骤以及该系统中实际活性配体结构的见解。