title: Detailed Mechanistic Studies on Palladium-Catalyzed Selective C-H Olefination with Aliphatic Alkenes: A Significant Influence of Proton Shuttling.
abstract: Directing group-assisted regioselective C-H olefination with electronically biased olefins is well studied. However, the incorporation of unactivated olefins has remained largely unsuccessful. A proper mechanistic understanding of olefination involving unactivated alkenes is therefore essential for enhancing their usage in future. In this Article, detailed experimental and computational mechanistic studies on palladium catalyzed C-H olefination with unactivated, aliphatic alkenes are described. The isolation of Pd(II) intermediates is shown to be effective for elucidating the elementary steps involved in catalytic olefination. Reaction rate and order determination, control experiments, isotopic labeling studies, and Hammett analysis have been used to understand the reaction mechanism. The results from these experimental studies implicate β-hydride elimination as the rate-determining step and that a mechanistic switch occurs between cationic and neutral pathway. Computational studies support this interpretation of the experimental evidence and are used to uncover the origins of selectivity.
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India.
authors.forename: Arghya
authors.initials: A
authors.lastname: Deb
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India.
authors.forename: Avijit
authors.initials: A
authors.lastname: Hazra
authors.affiliation: Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, United Kingdom.|State Key Laboratory of Elemento-Organic Chemistry, Nankai University , Tianjin 300071, People's Republic of China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Peng
authors.affiliation: Chemistry Research Laboratory, University of Oxford , Mansfield Road, Oxford OX1 3TA, United Kingdom.
authors.forename: Robert S
authors.identifier: 0000-0002-0104-4166
authors.initials: RS
authors.lastname: Paton
authors.affiliation: Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India.
authors.forename: Debabrata
authors.identifier: 0000-0001-8353-1306
authors.initials: D
authors.lastname: Maiti