Ir(I)-catalyzed intermolecular allylic amidation of ethyl allylic carbonates with soft nitrogen nucleophiles under completely "salt-free" conditions is described. A combination of [Ir(COD)Cl](2), a chiral phosphoramidite ligand L*, and DBU as a base in THF effects the reaction. The reaction appears to be quite general, accommodating a wide variety of R-groups and soft nitrogen nucleophiles, and proceeds with excellent regio- and enantioselectivities to afford the branched N-protected allylic amines. The developed reaction was conveniently utilized in the asymmetric synthesis of Boc protected alpha- and beta-amino acids as well as (-)-cytoxazone.
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http://dx.doi.org/10.1016/j.tetlet.2007.08.009 | DOI Listing |
J Org Chem
December 2024
Faculty of Pharmaceutical Sciences, Hokkaido University, Sapporo 060-0812, Japan.
Using amines in catalytic transfer hydrogenation (TH) is challenging, despite their potential availability as a hydrogen source. Here, we describe a photoredox/nickel-catalyzed TH of alkyne through an intermediary aminoalkyl Ni species. This reaction successfully provided functionalized ()-alkenes, such as (homo)allyl ethers, alcohols, and amides (/ = up to >99:1), and the reaction thus bypasses a limitation of substrate scope in TH using amine and a Lindlar catalyst.
View Article and Find Full Text PDFPolymers (Basel)
November 2024
Centro de Investigación en Química Aplicada, Department of Macromolecular Chemistry and Nanomaterials, Blvd Enrique Reyna #140, Saltillo 25294, Mexico.
Three novel bio-based monomers were synthesized through an amidation reaction involving allylated derivatives of coumaric, ferulic and phloretic acid and a diamine obtained from a thiol-ene coupling reaction between limonene and cysteamine. The monomers containing the enone bond of the cinnamic moiety underwent photoisomerization and photocycloaddition reactions upon UV light irradiation. All three monomers were photocured via thiol-ene photopolymerization using a glycerol-derived trifunctional thiol, resulting in fully bio-based poly(amide-thioether)s.
View Article and Find Full Text PDFChem Pharm Bull (Tokyo)
December 2024
Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts.
A total synthesis of javaberine A was achieved through a lithium amide-mediated intramolecular hydroamination of an N-allyl aminoalkene. The desired hydroamination was accomplished using an excess of i-PrNH with a substoichiometric amount of n-BuLi. Using an excess of both n-BuLi and i-PrNH led to tandem cyclization, however, resulting in the construction of a tricyclic structure through the formation of one C-N and two C-C bonds in a single operation.
View Article and Find Full Text PDFOrg Lett
December 2024
College of Chemistry and Materials Science, Hengyang Normal University, Hengyang 421000, People's Republic of China.
Herein we successfully utilize various directing groups to achieve a ligand-enabled nickel-catalyzed 1,2-borylalkylation of unactivated alkenes. A β-amino alcohol was employed as the ligand for non-asymmetric 1,2-borylalkylation of unactivated alkenes, while a bulky chiral diamine ligand was used to achieve the asymmetric 1,2-borylalkylation of allyl amides.
View Article and Find Full Text PDFAdv Sci (Weinh)
November 2024
State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, Frontiers Science Center for New Organic Matter, College of Chemistry, Nankai University, Tianjin, 300071, P. R. China.
Allylic amide moieties are commonly encountered in natural products and are privileged structures in pharmaceuticals and agrochemicals. Moreover, because allylic amide can be to converted into an array of high-value motifs, they have been widely employed in organic synthesis. However, the development of catalytic systems for intermolecular allylic amidation of olefins, particularly branched α-olefins, has proven to be challenging.
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