144461-87-0Relevant academic research and scientific papers
Photocatalytic Reductive Radical-Polar Crossover for a Base-Free Corey–Seebach Reaction
Crespi, Stefano,Donabauer, Karsten,K?nig, Burkhard,Murugesan, Kathiravan,Rozman, Ur?a
supporting information, p. 12945 - 12950 (2020/09/23)
A metal-free generation of carbanion nucleophiles is of prime importance in organic synthesis. Herein we report a photocatalytic approach to the Corey–Seebach reaction. The presented method operates under mild redox-neutral and base-free conditions giving the desired product with high functional group tolerance. The reaction is enabled by the combination of photo- and hydrogen atom transfer (HAT) catalysis. This catalytic merger allows a C?H to carbanion activation by the abstraction of a hydrogen atom followed by radical reduction. The generated nucleophilic intermediate is then capable of adding to carbonyl electrophiles. The obtained dithiane can be easily converted to the valuable α-hydroxy carbonyl in a subsequent step. The proposed reaction mechanism is supported by emission quenching, radical–radical homocoupling and deuterium labeling studies as well as by calculated redox-potentials and bond strengths.
New synthetic strategy for high-enantiopurity N-protected α-amino ketones and their derivatives by asymmetric hydrogenation
Sun, Tian,Hou, Guohua,Ma, Miaofeng,Zhang, Xumu
, p. 253 - 256 (2011/04/16)
Asymmetric hydrogenation of α-dehydroamino ketones catalyzed by a rhodium-chiral phosphorus ligand complex (up to 99% ee, 1000 TON), represents an efficient approach to chiral α-amino ketones. The reduction of α-amino ketones catalyzed by palladium on carbon (Pd/C) leads to amphetamine precursors with quantitative yield and no significant enantioselectivity loss.
Electrophilic amination of ketone enolates mediated by the DiTOX asymmetric building block: Enantioselective formal synthesis of α-aminoacids
Bulman Page, Philip C.,McKenzie, Michael J.,Allin, Steven M.,Buckle, Derek R.
, p. 9683 - 9695 (2007/10/03)
Diastereoselective electrophilic amination of enolates derived from 2-acyl-1,3-dithiane 1-oxides is used as the key step for an enantioselective synthesis of two α-hydrazido carboxylic acids, well-known precursors of α-amino acids. (C) 2000 Elsevier Science Ltd.
An efficient photo-SET-induced cleavage of dithiane-carbonyl adducts and its relevance to the development of photoremovable protecting groups for ketones and aldehydes
McHale, William A.,Kutateladze, Andrei G.
, p. 9924 - 9931 (2007/10/03)
Irradiation of dithiane-aldehyde/ketone adducts in the presence of benzophenone leads to C-C bond cleavage regenerating the carbonyl compounds. It is established that the mechanism of this reaction involves photochemically induced single electron transfer from the dithiane moiety to the excited molecule of ET-photosensitizer, accompanied by mesolytic C-C cleavage in the generated cation-radical, which is assisted by the anion- radical of benzophenone. This mechanism is confirmed by a Hammett plot study of the cleavage in the dithiane adducts of substituted aromatic aldehydes and a deuterium kinetic isotope effect study. Ab initio computations at UHF/6- 31G* and MP2/6-31G* levels of theory in conjunction with self-consistent reaction field (self-consistent isodensity-polarized continuum model), to account for the solvent effect, also support the experimental findings. The reaction is most efficient for protection of aromatic aldehydes and ketones and aliphatic ketones, and is a novel method for protecting carbonyl functionalities with a photoremovable group.
Enantioselective preparation of 2-substituted-1,3-dithiane 1-oxides using modified Sharpless sulphoxidation procedures
Page, Philip C. Bulman,Wilkes, Robin D.,Namwindwa, Ernest S.,Witty, Michael J.
, p. 2125 - 2154 (2007/10/03)
Enantioselective sulphoxidation of a wide range of 2-substituted-1,3-diathianes has been carried out using modified Sharpless conditions to furnish the corresponding sulphoxides in optically enriched form. Deacylation of 2-acyl-1,3-dithiane 1-oxide deriva
Diastereoselectivity in the Addition of Grignard Reagents to Ketones Controlled by the 1,3-Dithiane 1-Oxide Asymmetric Building Block
Page, Philip C. Bulman,Prodger, Jeremy C.,Westwood, Donald
, p. 10355 - 10368 (2007/10/02)
2-Acyl-1,3-dithiane 1-oxide undergo diastereoselective addition of Grignard reagents; the degree of selectivity observed is highly dependent upon the solvent and the halide counter-ion used; very high selectivities have been observed under certain reactio
A convenient preparation of symmetrical and unsymmetrical 1,2-diketones: Application to fluorinated phenytoin synthesis
Page,Graham,Park
, p. 7265 - 7274 (2007/10/02)
1,2-Diketones are efficiently produced in two steps by reaction of aldehydes with anions derived from 2-substituted dithianes followed by treatment of the resulting alcoholis with NBS in aqueous acetone; phenytoin derivatives were prepared from these diketones by a standard method involving treatment with urea and potassium hydroxide under reflux.
