1460-02-2Relevant articles and documents
Carbon dioxide promoted palladium-catalyzed cyclotrimerization of alkynes in water
Li, Jin-Heng,Xie, Ye-Xiang
, p. 1737 - 1743 (2004)
In water, CO2 was found to promote the palladium-catalyzed cyclotrimerization of alkynes. In the presence of PdCl2, CuCl 2, and CO2, both aryl and alkylalkynes afforded the corresponding cyclotrimerization products regioselectively in high yields. However, tert-butylacetylene bearing a bulk group gave a dimerization product.
Krauss,Stach
, p. 280,285,289 (1969)
Bailey,P.M. et al.
, p. 238 - 239 (1976)
Synthesis, crystal structure, and nonlinear optical behavior of β-unsubstituted meso-meso E-vinylene-linked porphyrin dimers
Frampton, Michael J.,Akdas, Huriye,Cowley, Andrew R.,Rogers, Joy E.,Slagle, Jonathan E.,Fleitz, Paul A.,Drobizhev, Mikhail,Rebane, Aleksander,Anderson, Harry L.
, p. 5365 - 5368 (2005)
(Chemical Equation Presented) A vinylene-linked porphyrin dimer, with no substituents at the β-positions, has been synthesized by CuI/CsF promoted Stille coupling. In the crystal structure of this dimer, the C2H 2 bridge is twisted by 45° relative to the plane of the porphyrins. The absorption, emission spectra, and electrochemistry reveal substantial porphyrin-porphyrin π-conjugation. The triplet excited-state absorption spectrum of this dimer makes it suitable for reverse saturable absorption at 710-900 nm.
Kaiser,Maitlis
, p. 942 (1970)
Surprising Reactivity of Very Crowded Phosphinic Derivatives
Baceiredo, Antoine,Bertrand, Guy,Mazerolles, Pierre,Majoral, Jean-Pierre
, p. 1197 - 1198 (1981)
An example of intramolecular cyclisation of a crowded phosphinic chloride via loss of hydrogen chloride and formation of a phosphorus-carbon bond is described; unexpected cleavage of an acyclic phosphorus-carbon bond is also reported.
CuCl2-induced regiospecifical synthesis of benzene derivatives in the palladium-catalyzed cyclotrimerization of alkynes
Li,Jiang,Chen
, p. 3627 - 3629 (2001)
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Ditto,S.R. et al.
, p. 894 - 896 (1979)
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Photoredox catalysis on unactivated substrates with strongly reducing iridium photosensitizers
Shon, Jong-Hwa,Kim, Dooyoung,Rathnayake, Manjula D.,Sittel, Steven,Weaver, Jimmie,Teets, Thomas S.
, p. 4069 - 4078 (2021/04/06)
Photoredox catalysis has emerged as a powerful strategy in synthetic organic chemistry, but substrates that are difficult to reduce either require complex reaction conditions or are not amenable at all to photoredox transformations. In this work, we show that strong bis-cyclometalated iridium photoreductants with electron-rich β-diketiminate (NacNac) ancillary ligands enable high-yielding photoredox transformations of challenging substrates with very simple reaction conditions that require only a single sacrificial reagent. Using blue or green visible-light activation we demonstrate a variety of reactions, which include hydrodehalogenation, cyclization, intramolecular radical addition, and prenylationviaradical-mediated pathways, with optimized conditions that only require the photocatalyst and a sacrificial reductant/hydrogen atom donor. Many of these reactions involve organobromide and organochloride substrates which in the past have had limited utility in photoredox catalysis. This work paves the way for the continued expansion of the substrate scope in photoredox catalysis.
Linear Hydroaminoalkylation Products from Alkyl-Substituted Alkenes
Warsitz, Michael,Doye, Sven
supporting information, p. 15121 - 15125 (2020/10/23)
The regioselective conversion of alkyl-substituted alkenes into linear hydroaminoalkylation products represents a strongly desirable synthetic transformation. In particular, such conversions of N-methylamine derivatives are of great scientific interest, because they would give direct access to important amines with unbranched alkyl chains. Herein, we present a new one-pot procedure that includes an initial alkene hydroaminoalkylation with an α-silylated amine substrate and a subsequent protodesilylation reaction that delivers linear hydroaminoalkylation products with high selectivity from simple alkyl-substituted alkenes. For that purpose, new titanium catalysts have been developed, which are able to activate the α-C?H bond of more challenging α-silylated amine substrates. In addition, a direct relationship between the ligand structure of the new catalysts and the obtained regioselectivity is described.
Combined Photoredox and Iron Catalysis for the Cyclotrimerization of Alkynes
Chakraborty, Uttam,Jacobi von Wangelin, Axel,Neumeier, Michael,Perez-Ruiz, Raul,Schaarschmidt, Dieter,de la Pena O'Shea, Victor
supporting information, p. 13473 - 13478 (2020/06/02)
Successful combinations of visible-light photocatalysis with metal catalysis have recently enabled the development of hitherto unknown chemical reactions. Dual mechanisms from merging metal-free photocatalysts and earth-abundant metal catalysts are still in their infancy. We report a photo-organo-iron-catalyzed cyclotrimerization of alkynes by photoredox activation of a ligand-free Fe catalyst. The reaction operates under very mild conditions (visible light, 20 °C, 1 h) with 1–2 mol percent loading of the three catalysts (dye, amine, FeCl2).