72277-22-6Relevant academic research and scientific papers
Carbonyls as Latent Alkyl Carbanions for Conjugate Additions
Dai, Xi-Jie,Wang, Haining,Li, Chao-Jun
supporting information, p. 6302 - 6306 (2017/05/19)
Conjugate addition of carbon nucleophiles to electron-deficient olefins is one of the most powerful methods for forming carbon–carbon bonds. Despite great achievements in controlling the selectivity, variation of the carbon nucleophiles remains largely underexplored, with this approach relying mostly on organometallic reagents. Herein, we report that naturally abundant carbonyls can act as latent carbon nucleophiles for conjugate additions through a ruthenium-catalyzed process, with water and nitrogen as innocuous byproducts. The key to our success is homogeneous ruthenium(II) catalysis, combined with phosphines as spectator ligands and hydrazine as the reducing agent. This chemistry allows the incorporation of highly functionalized alkyl fragments into a vast array of electron-deficient olefins under mild reaction conditions in a reaction complementary to the classical organometallic-reagent-based conjugate additions mediated or catalyzed by “soft” transition metals.
Nickel-catalyzed asymmetric transfer hydrogenation of conjugated olefins
Guo, Siyu,Yang, Peng,Zhou, Jianrong
supporting information, p. 12115 - 12117 (2015/07/28)
Asymmetric transfer hydrogenation of electron-deficient olefins is realized with nickel catalysts supported by strongly σ-donating bisphosphines. Deuterium labeling experiments point to a reaction sequence of formate decarboxylation, asymmetric hydride in
Highly enantioselective iridium-catalyzed hydrogenation of α,β-unsaturated esters
Li, Jia-Qi,Quan, Xu,Andersson, Pher G.
supporting information, p. 10609 - 10616 (2012/11/07)
α,β-Unsaturated esters have been employed as substrates in iridium-catalyzed asymmetric hydrogenation. Full conversions and good to excellent enantioselectivities (up to 99 % ee) were obtained for a broad range of substrates with both aromatic- and aliphatic substituents on the prochiral carbon. The hydrogenated products are highly useful as building blocks in the synthesis of a variety of natural products and pharmaceuticals. Asymmetric hydrogenation: A variety of α,β-unsaturated esters were hydrogenated with high enantioselectivities (see scheme). The hydrogenated products have been used in synthetic transformations as well as in formal total syntheses. Copyright
Pd-catalyzed cleavage of benzylic nitro bonds: New opportunities for asymmetric synthesis
Fessard, Thomas C.,Motoyoshi, Hajime,Carreira, Erick M.
, p. 2078 - 2081 (2008/02/13)
Without a trace: Benzylic nitroalkanes are reduced to the corresponding parent alkanes in good yields by using a simple procedure involving heterolytic C-N bond cleavage (see scheme). Traceless removal of the nitro group leaves behind a stereogenic center that may otherwise be difficult to install. This reaction significantly expands the scope of building blocks that can be accessed. (Chemical Equation Presented)
Tetramethylethylene diamine/trimethylsilyl chloride mediated addition of benzyl copper reagents to α,β-unsaturated esters
Van Heerden, Pieter S.,Bezuidenhoudt, Barend C. B.,Ferreira, Daneel
, p. 12313 - 12322 (2007/10/03)
Several benzylic copper reagents, benzylcopper, 4-methoxybenzylcopper and 1-phenylethylcopper, facilitate the conjugate addition of the corresponding benzyl ligands to α,β-enoates in the presence of tetramethylethylene diamine and trimethylsilyl chloride in high yields.
CONJUGATE ADDITION OF BENZYL COPPER REAGENTS TO α,β-ENOATES AND -ENONES.
Heerden, Pieter S. van,Bezuidenhoudt, Barend C. B.,Steenkamp, Jacobus A.,Ferreira, Daneel
, p. 2383 - 2386 (2007/10/02)
Several benzylic copper reagents, BnCu(CN)MgCl, Bn2CuMgCl, BnCu-TMSCl-HMPA, and BnCu-TMSCl-TMEDA, facilitate the conjugate addition of the benzyl ligand to α,b-enones, but only BnCu-TMSCl-TMEDA gave high yields with α,β-unsaturated esters.
Dimeric Metal Complexes as Mediator for Radical C-C Bond-Forming Reactions
Giese, Bernd,Thoma, Gebhard
, p. 1135 - 1142 (2007/10/02)
Irradiation of dicarbonyl(η5-cyclopentadienyl)iron dimer 1 or decacarbonyldimanganese (2) in the presence of alkyl halides leads to C-centered radicals which can be trapped by alkenes and yields saturated and/or unsaturated addition products.Carbon radicals are generated via halogen abstraction by the initially formed metal-centered radicals resulting from homolysis of the metal-metal bond of dimeric mediators 1 and 2.No reaction occurs using octacarbonyl dicobalt (3).
Directed ortho metalation reactions. Convergent synthesis of "angular" anthracyclinones ochromycinone and X-14881 C
Katsuura, K.,Snieckus, V.
, p. 124 - 130 (2007/10/02)
Convergent syntheses of the benzanthraquinone natural products X-14881 C (2c) and ochromycinone (2d) have been achieved using aromatic directed metalation strategies.Key steps involve (a) the condensations of dilithiated cis-tetralol (13a) with the ald
DIRECTED ORTHO METALATION REACTIONS. SYNTHESIS OF NATURALLY-OCCURRING BENZANTHRAQUINONES X-14881 C AND OCHROMYCINONE
Katsuura, K.,Snieckus, V.
, p. 9 - 12 (2007/10/02)
The synthesis of the benzanthraquinone natural products X-14881 C (1c) and ochromycinone (1a) via an aromatic directed metalation strategy (Scheme 1) is described.
