Hao Han, Manßen Manfred, Schafer Laurel L
Department of Chemistry, University of Toronto Toronto Ontario M5S 3H6 Canada.
Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen Auf der Morgenstelle 18 72076 Tübingen Germany.
Chem Sci. 2023 Apr 19;14(18):4928-4934. doi: 10.1039/d3sc00042g. eCollection 2023 May 10.
Using a tantalum ureate pre-catalyst, photocatalytic hydroaminoalkylation of unactivated alkenes with unprotected amines at room temperature is demonstrated. The combination of Ta(CHSiMe)Cl and a ureate ligand with a saturated cyclic backbone resulted in this unique reactivity. Preliminary investigations of the reaction mechanism suggest that both the thermal and photocatalytic hydroaminoalkylation reactions begin with N-H bond activation and subsequent metallaaziridine formation. However, a select tantalum ureate complex, through ligand to metal charge transfer (LMCT), results in photocatalyzed homolytic metal-carbon bond cleavage and subsequent addition to unactivated alkene to afford the desired carbon-carbon bond formation. Origins of ligand effects on promoting homolytic metal-carbon bond cleavage are explored computationally to support enhanced ligand design efforts.
使用钽尿酸盐预催化剂，在室温下实现了未活化烯烃与未保护胺的光催化氢胺烷基化反应。Ta(CHSiMe)Cl与具有饱和环状骨架的尿酸盐配体的组合产生了这种独特的反应活性。对反应机理的初步研究表明，热催化和光催化氢胺烷基化反应均始于N-H键活化及随后的金属氮杂环丙烷形成。然而，一种特定的钽尿酸盐配合物通过配体到金属的电荷转移（LMCT），导致光催化均裂金属-碳键裂解，随后加成到未活化烯烃上，从而实现所需的碳-碳键形成。通过计算探索了配体对促进均裂金属-碳键裂解的影响来源，以支持增强配体设计的工作。
