A Convergent Synthesis Approach to Uranium-Carbon Triple Bonds for Alkyne Metathesis Reactions.

在过渡金属化学中，次烷基配合物由于其在炔复分解催化中的作用而引起人们的兴趣。用于炔复分解反应的最著名的催化剂具有式RC RMM（OR）3，其中M = Mo，W，是可商购的化合物，并且最初由R.施洛克康明斯小组在炔复分解反应方面经验丰富，并做出了贡献。结果表明，式R1 C = Mo（N[i-Pr]Ar）3的络合物是“通用的”催化剂前体，因为它们与3 R2 OH的处理产生式R1 C = Mo（OR 2）3的活性炔复分解催化剂。迈耶研究计划的一个主要组成部分是在反应性铀络合物中激活小分子。这些复合物具有可用于反应化学的空间保护的单一结合位点。这项工作的一个亮点是通过单一的氧铀相互作用（η1-O-CO2）结合和活化二氧化碳。在本研究中，我们将tacn-三酚盐铀平台与康明斯的前过渡金属试剂相结合，体现了“会聚合成”的原则。这一聚合努力的目的是发现第一个铀次烷基（U CR）配合物，并探测它们在炔复分解反应中的活性。

In transition-metal chemistry, alkylidyne complexes are of interest for the role that they play in alkyne metathesis catalysis. The best-known catalysts for the alkyne metathesis reaction have the formula RC≡M(OR)3 with M = Mo, W, are commercially available compounds, and were originally discovered by R. Schrock. The Cummins group is experienced with and has made contributions to alkyne metathesis. It was shown that complexes of the formula R1C≡Mo(N[i-Pr]Ar)3 are “universal” catalyst precursors, because their treatment with 3 R2OH produces active alkyne metathesis catalysts of formula R1C≡Mo(OR2)3. A major component of the Meyer research program is the activation of small molecules at reactive uranium complexes. These complexes have a sterically protected single binding site available for reaction chemistry. A highlight of this work has been the binding and activation of carbon dioxide through a single oxygenuranium interaction (η1-O-CO2). For the research proposed herein, the principle of “convergent synthesis” is embodied by our combination of the tacn-triphenolate uranium platform with Cummins’ early transition-metal reagents. The aim of this convergent effort is to uncover the first uranium alkylidyne (U≡CR) complexes and to probe their activity in alkyne metathesis.