259825-69-9Relevant academic research and scientific papers
Synthesis of silaoxazolinium salts bearing weakly coordinating anions: Structures and catalytic activities in the aldol reaction
Chandra Sheker Reddy, Anugu,Chen, Zhang,Hatanaka, Tohru,Minami, Tatsuya,Hatanaka, Yasuo
, p. 3575 - 3582 (2013/07/26)
The synthesis and structures of silaoxazolinium salts 2 and their application to the catalytic Mukaiyama aldol reaction are described. The reaction of (N-amidomethyl)dimethylchlorosilane (1a) or (N-amidomethyl) bis(trimethylsilyl)chlorosilane (1b) with me
Neodymium(III)-mediated reformatsky-type reactions of α-halo ketones with carbonyl compounds
Kirsch, Stefan F.,Liebert, Clemence
, p. 3711 - 3717 (2008/03/18)
In a neodymium(III) iodide induced process, α-bromo ketones 1 and aldehydes 2 are effectively converted into aldol products 3. This Reformatsky-type reaction proceeds through the formation of a neodymium enolate at room temperature in CH2Cl2. The analogous reaction in the presence of NdBr3/NaI at 50°C in THF favors the formation of corresponding aldol-Tishchenko products 5 in good yields. Studies to define the scope and limitations of these reactions mediated by neodymium(III) salts are also described. Wiley-VCH Verlag GmbH & Co. KGaA, 2007.
Aldol reactions of α-bromoalkyl phenyl ketones and aldehydes with tin(IV) iodide and tetrabutylammonium iodide
Masuyama, Yoshiro,Ohtsuka, Masaru,Kondo, Ayako
, p. 3346 - 3348 (2008/09/18)
Aldol reactions of α-bromoacetophenone and aldehydes in dichloromethane produced the corresponding E-α,β-unsaturated ketones at 25 °C with one equimolar amount of tin(IV) iodide, one equimolar amount of tetrabutylammonium iodide and one equimolar amount of N,N- diisopropylethylamine, and produced the corresponding β-hydroxy ketones at -80 °C with one equimolar amount of tin(IV) iodide and two equimolar amounts of tetrabutylammonium iodide. Using one equimolar amount of tin(IV) iodide and two equimolar amounts of tetrabutylammonium iodide at -80 °C in dichloromethane, α-bromopropiophenone reacted with aldehydes to afford the corresponding syn-α-methyl-β-hydroxy ketones selectively. Georg Thieme Verlag Stuttgart.
Felkin-Anh stereoselectivity in cycloadditions of acetylketene: Evidence for a concerted, pseudopericyclic pathway
Shumway,Ham,Moer,Whittlesey,Birney
, p. 7731 - 7739 (2007/10/03)
The cycloadditions of acetylketene with α-chiral aldehydes and ketones are shown to be diastereoselective, forming a tertiary or quaternary chiral center at an acetal or ketal carbon with good stereocontrol. X-ray crystallography of a minor product (5b) shows that the major products (e.g., 4b) are those predicted by the Felkin-Anh model. Transition states are reported at the MP2/6-31G* level for the addition of ethanal to formylketene and at the B3LYP/6-31G* level for the addition of 2-phenylpropanal. The ground-state conformations of the reactants and products are used to rationalize the relative energies and geometries of the transition states without the need to invoke the Cieplak hypothesis. However, chiral substituents on the α-oxoketene show no diastereoselectivity. These experimental and computational results are only consistent with the nearly planar, pseudopericyclic transition state previously proposed.
Double Stereoselection in the Aldol-type Synthesis of γ-Methyl and γ-Alkoxy β-Hydroxy Ketones Mediated by α-Sulphinyl Hydrazones
Annunziata, Rita,Cinquini, Mauro,Cozzi, Franco,Gilardi, Amilcare,Cardani, Silvia,et al.
, p. 255 - 260 (2007/10/02)
Optically active γ-methyl-β-hydroxy and γ-alkoxy-β-hydroxy ketones have been obtained by condensing chiral racemic aldehydes with chiral α-sulphinyl hydrazones.Good to excellent enantioselectivity and diastereoselectivity, both strongly dependent on the n
