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

在过渡金属化学中，亚烷基化合物因其在炔烃歧化反应中所起的作用而备受关注。最著名的用于炔烃歧化反应的催化剂具有式RC≡M(OR)3(M=Mo，W)，是商业上可用的化合物，最初由R.Schrock发现。康明斯集团在炔烃复分解方面经验丰富，并做出了贡献。结果表明，式R1C≡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 R2OH反应生成了式R1C≡Mo(OR2)3的活性烯烃歧化催化剂。Meyer研究计划的一个主要成分是活性铀络合物上的小分子被活化。这些络合物具有空间保护的单一结合部位，可用于反应化学。这项工作的一个亮点是通过单一的氧-铀相互作用(η1-O-CO2)结合和激活二氧化碳。对于本文提出的研究，“收敛合成”的原则体现为我们将焦炭-三酚铀平台与康明斯早期的过渡金属试剂相结合。这一融合努力的目的是发现第一个铀烷基烷(U-≡-CR)络合物，并探索它们在炔烃歧化反应中的活性。

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.