51024-76-1Relevant academic research and scientific papers
Selecting double bond positions with a single cation-responsive iridium olefin isomerization catalyst
Camp, Andrew M.,Kita, Matthew R.,Blackburn, P. Thomas,Dodge, Henry M.,Chen, Chun-Hsing,Miller, Alexander J.M.
, p. 2792 - 2800 (2021)
The catalytic transposition of double bonds holds promise as an ideal route to alkenes of value as fragrances, commodity chemicals, and pharmaceuticals; yet, selective access to specific isomers is a challenge, normally requiring independent development of different catalysts for different products. In this work, a single cation-responsive iridium catalyst selectively produces either of two different internal alkene isomers. In the absence of salts, a single positional isomerization of 1-butene derivatives furnishes 2-alkenes with exceptional regioselectivity and stereoselectivity. The same catalyst, in the presence of Na+, mediates two positional isomerizations to produce 3-alkenes. The synthesis of new iridium pincer-crown ether catalysts based on an aza-18-crown-6 ether proved instrumental in achieving cation-controlled selectivity. Experimental and computational studies guided the development of a mechanistic model that explains the observed selectivity for various functionalized 1-butenes, providing insight into strategies for catalyst development based on noncovalent modifications.
Organic Photochemistry with 6.7-ev Photons: γ,δ-Unsaturated Ketones
Leigh, William J.,Srinivasan, R.
, p. 4424 - 4429 (2007/10/02)
The photochemistry of a series of acyclic, aliphatic γ,δ-unsaturated ketones in pentane solution with 185-nm light has been investigated.The variety of products formed can be rationalized as arising from discrete reactions of the individually excited chromophores.Neither intramolecular energy transfer nor internal conversion leading to population of the lowest (n,?*) singlet state are competitive with product formation at 185 nm.The mechanism of alkyne formation in the solution-phase photolysis of these and terminal alkenes at 185 nm is elucidated by using a deuterated derivative, and the reaction is postulated to proceed from the olefinic ?,?* singlet state.
