1396756-66-3Relevant academic research and scientific papers
Rh-Catalyzed domino synthesis of 4-hydroxy-3-methylcoumarins via branch-selective hydroacylation
Rao, Maddali L.N.,Ramakrishna, Boddu S.,Nand, Sachchida
, p. 9275 - 9279 (2019)
A Rh-catalyzed domino synthesis of 4-hydroxy-3-methylcoumarins via branch-selective hydroacylation of acrylates and acrylamides using salicylaldehydes is described. This protocol under phosphine-free Rh-catalyzed conditions provided 4-hydroxy-3-methylcoum
Rhodium-phosphoramidite catalyzed alkene hydroacylation: Mechanism and octaketide natural product synthesis
Von Delius, Max,Le, Christine M.,Dong, Vy M.
supporting information, p. 15022 - 15032 (2012/11/06)
We describe a method that allows salicylaldehyde derivatives to be coupled with a wide range of unactivated alkenes at catalyst loadings as low as 2 mol %. A chiral phosphoramidite ligand and the precise stoichiometry of heterogeneous base are key for high catalytic activity and linear regioselectivity. This protocol was applied in the atom- and step-economical synthesis of eight biologically active octaketide natural products, including anticancer drug candidate cytosporone B. Mechanistic studies provide insight on parameters affecting decarbonylation, a side reaction that limits the turnover number for catalytic hydroacylation. Deuterium labeling studies show that branched hydride insertion is fully reversible, whereas linear hydride insertion is largely irreversible and turnover-limiting. We propose that ligand (R a,R,R)-SIPHOS-PE effectively suppresses decarbonylation, and helps favor a turnover-limiting insertion, by lowering the barrier for reductive elimination in the linear-selective pathway. Together, these factors enable high reactivity and regioselectivity.
