Abstract
Transition-metal-catalyzed alkene hydrosilylation is one of the most important homogeneous catalytic reactions, and the development of methods that use base metals, especially iron, as catalysts for this transformation is a growing area of research. However, the limited number of ligand scaffolds applicable for base-metal-catalyzed alkene hydrosilylation has seriously hindered advances in this area. Herein, we report the use of 1,10-phenanthroline ligands in base-metal catalysts for alkene hydrosilylation. In particular, iron catalysts with 2,9-diaryl-1,10-phenanthroline ligands exhibit unexpected reactivity and selectivity for hydrosilylation of alkenes, including unique benzylic selectivity with internal alkenes, Markovnikov selectivity with terminal styrenes and 1,3-dienes, and excellent activity toward aliphatic terminal alkenes. According to the mechanistic studies, the unusual benzylic selectivity of this hydrosilylation initiates from π–π interaction between the phenyl of the alkene and the phenanthroline of the ligand. This ligand scaffold and its unique catalytic model will open possibilities for base-metal-catalyzed hydrosilylation reactions.
Highlights
Transition-metal-catalyzed alkene hydrosilylation is one of the most important homogeneous catalytic reactions, and the development of methods that use base metals, especially iron, as catalysts for this transformation is a growing area of research
We began by evaluating the catalytic activity of 2 for hydrosilylation of internal alkenes
Catalyst 2b developed in this study showed excellent Markovnikov selectivity (≥98%) and high yields (88–95%) in the hydrosilylation of terminal styrenes 9 (Table 3)
Summary
Transition-metal-catalyzed alkene hydrosilylation is one of the most important homogeneous catalytic reactions, and the development of methods that use base metals, especially iron, as catalysts for this transformation is a growing area of research. According to the mechanistic studies, the unusual benzylic selectivity of this hydrosilylation initiates from π–π interaction between the phenyl of the alkene and the phenanthroline of the ligand This ligand scaffold and its unique catalytic model will open possibilities for basemetal-catalyzed hydrosilylation reactions. As part of our ongoing work on ironcatalyzed reactions[17,18,19], we report the development of bidentate ligands based on a 1,10-phenanthroline scaffold (Darphen, 1) and their use for highly efficient iron-catalyzed alkene hydrosilylation Catalysts bearing these ligands showed unexpected substrate reactivity and selectivity for iron-catalyzed hydrosilylation of alkenes, including unique benzylic selectivity for internal alkenes, Markovnikov selectivity for terminal styrenes and 1,3-dienes, and excellent activity toward aliphatic terminal alkenes. The mechanistic studies indicate that the benzylic selectivity of this hydrosilylation initiates from π–π interaction between the phenyl of the alkene and the phenanthroline of the ligand
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
