- Visible-Light-Mediated Heterocycle Functionalization via Geometrically Interrupted [2+2] Cycloaddition
-
The [2+2] photocycloaddition is the most valuable and intensively investigated photochemical process. Here we demonstrate that irradiation of N-acryloyl heterocycles with blue LED light (440 nm) in the presence of an IrIII complex leads to efficient and high yielding fused γ-lactam formation across a range of substituted heterocycles. Quantum calculations show that the reaction proceeds via cyclization in the triplet excited state to yield a 1,4-diradical; intersystem crossing leads preferentially to the closed shell singlet zwitterion. This is geometrically restricted from undergoing recombination to yield a cyclobutane by the planarity of the amide substituent. A prototropic shift leads to the observed bicyclic products in what can be viewed as an interrupted [2+2] cycloaddition.
- Alegre-Requena, Juan V.,Mekereeya, Aroonroj,Paton, Robert S.,Popescu, Mihai V.,Smith, Martin D.
-
-
Read Online
- Amino- and azidocarbonylation of iodoalkenes
-
Iodoalkenes, available from ketones via their hydrazones, underwent palladium-catalysed azidocarbonylation. Depending on the structure of the acyl azides, consecutive hydrolysis toward corresponding primary amides was observed. ‘Direct’ aminocarbonylation
- Mikle, Gábor,Skoda-F?ldes, Rita,Kollár, László
-
-
- Pyridine-Enabled C-N Bond Activation for the Rapid Construction of Amides and 4-Pyridylglyoxamides by Cooperative Palladium/Copper Catalysis
-
A pyridine-enabled C-N bond activation of peptidomimetics employing cooperative palladium/copper catalysis in water is developed. Diverse amides and 4-pyridylglyoxamides are simultaneously synthesized through two steps from commercially available materials in a rapid, environmentally friendly, and high atom-economical manner.
- Song, Liangliang,Claessen, Sander,Van Der Eycken, Erik V.
-
p. 8045 - 8054
(2020/07/15)
-
- Hydroaminocarbonylation of Alkynes to Produce Primary α,β-Unsaturated Amides Using NH4HCO3 Dually as Ammonia Surrogate and Br?nsted Acid Additive
-
By using NH4HCO3 dually as ammonia surrogate and Br?nsted acid additive, the production of primary α,β-unsaturated amides via hydroaminocarbonylation of alkynes was accomplished efficiently. The advantages of using the solid and inexpensive NH4HCO3 included: (1) the facile and clean manipulation without presence of stinky gaseous NH3 or liquids organic amines, (2) the inhibition of the subsequent dehydration and hydrolysis of amides due to its weak basicity, and (3) the facilitated formation of Pd?H catalytic active species by the released H2CO3 serving as a weak Br?nsted acid additive. In addition, the diphopshine of Dppp with the natural bite angle (βn) of 91° was found indispensable to spur the performance of the palladium catalyst for this reaction. Both terminal and internal phenylacetylene derivatives could be used as the substrates, affording the corresponding primary α,β-unsaturated amides in good yields along with excellent regio-selectivities to the branched ones.
- Wang, Dong-Liang,Guo, Wen-Di,Zhou, Qing,Liu, Lei,Lu, Yong,Liu, Ye
-
p. 4264 - 4268
(2018/09/06)
-
- Palladium-Catalyzed Regioselective Hydroaminocarbonylation of Alkynes to α,β-Unsaturated Primary Amides with Ammonium Chloride
-
α,β-Unsaturated primary amides have found numerous applications in drug development, organic materials, and polymer sciences. However, the catalytic synthesis of α,β-unsaturated primary amides via carbonylation of alkynes has long been an elusive endeavor. Here, we report a novel palladium-catalyzed hydroaminocarbonylation of alkynes with NH4Cl as the amine source, enabling the highly chemo- and regioselective synthesis of α,β-unsaturated primary amides. A variety of alkynes, including aromatic alkynes, aliphatic alkynes, terminal alkynes, internal alkynes, as well as diynes with various functional groups, react well. The method turns the parasitic noncoordination ability of ammonium salts into a strategic advantage, enabling the gram-scale reaction to be performed in the presence of 0.05 mol % of catalyst with excellent selectivity.
- Ji, Xiaolei,Gao, Bao,Zhou, Xibing,Liu, Zongjian,Huang, Hanmin
-
p. 10134 - 10141
(2018/07/09)
-
- Convenient synthesis of various substituted homotaurines from alk-2-enamides
-
Various substituted homotaurines (=3-aminopropane-1-sulfonic acids) 6 were readily synthesized in satisfactory to good yields via the Michael addition of thioacetic acid to alk-2-enamides 3 (→4), followed by LiAlH4 reduction (→5) and performic acid oxidation (Scheme 1). The configuration of 'anti'-disubstituted homotaurine 'anti'-6h was deduced from the 3-(acetylthio)alkanamide (=S-(3-amino-1,2-dimethyl-3-oxopropyl) ethanethioate)'anti'-4h formed in the Michael addition, which was identified via the Karplus equation analysis, and confirmed by X-ray diffraction analysis. The current route is an efficient method to synthesize diverse substituted homotaurines, including 1-, 2-, and N-monosubstituted, as well as 1,2-, 1,N-, 2,N-, and N,N-disubstituted homotaurines (Table). Copyright
- Nai, Youfeng,Xu, Jiaxi
-
p. 1355 - 1365
(2013/08/23)
-
- Preparation of primary amides from functionalized organozinc halides
-
Organozinc halides, which are prepared either by direct zinc insertion or halogen-magnesium exchange and subsequent transmetalation with ZnCl2, react smoothly with commercially available trichloroacetyl isocyanate to give, after hydrolysis, the corresponding primary amides. This method is compatible with a variety of functional groups such as an ester or a cyano group. Also heterocyclic-, alkenyl, and acetylenic zinc reagents are converted to the corresponding primary amides under these conditions.
- Schade, Matthias A.,Manolikakes, Georg,Knochel, Paul
-
supporting information; experimental part
p. 3648 - 3650
(2010/11/04)
-