55409-09-1Relevant articles and documents
The Direct Conversion of α-Hydroxyketones to Alkynes
Ghiringhelli, Francesca,Nattmann, Lukas,Bognar, Sabine,Van Gemmeren, Manuel
, p. 983 - 993 (2019/01/24)
Alkynes are highly important functional groups in organic chemistry, both as part of target structures and as versatile synthetic intermediates. In this study, a protocol for the direct conversion of α-hydroxyketones to alkynes is reported. In combination with the variety of synthetic methods that generate the required starting materials by forming the central C-C bond, it enables a highly versatile fragment coupling approach toward alkynes. A broad scope for this novel transformation is shown alongside mechanistic insights. Furthermore, the utility of our protocol is demonstrated through its application in concert with varied α-hydroxyketone syntheses, giving access to a broad spectrum of alkynes.
Exerting control over the acyloin reaction
Donohoe, Timothy J.,Jahanshahi, Ali,Tucker, Michael J.,Bhatti, Farrah L.,Roslan, Ishmael A.,Kabeshov, Mikhail,Wrigley, Gail
, p. 5849 - 5851 (2011/06/27)
A synthetic method for conducting the acyloin reaction using electron transfer in solution is reported. By linking two esters via their oxygen atoms, it was possible to perform crossed acyloin reactions between two different ester functionalities and display a high degree of preference for an intramolecular coupling process.
Oxidation of secondary alcohols with phenyltrimethylammonium tribromide in the presence of a catalytic amount of antimony(III) bromide or copper(II) bromide
Sayama, Shinsei,Onami, Tetsuo
, p. 2369 - 2373 (2007/10/03)
The oxidation of alcohols was carried out with phenyltrimethylammonium tribromide in the presence of a catalytic amount of SbBr3 or CuBr2. 1,2-Diols, such as hydrobenzoin, were converted into 1,2-diketones or α-ketols without oxidative cleavage of the glycol C-C bond at room temperature. A variety of secondary alcohols were also oxidized to the corresponding carbonyl compounds in a chemoselective manner.
New coupling reactions of some acyl chlorides with samarium diiodide in the presence of samarium: Carbinols from three acyl units
Clausen, Christian,Weidner, Ingo,Butenschoen, Holger
, p. 3799 - 3806 (2007/10/03)
A mixture of samarium(II) iodide and samarium can induce a coupling reaction of three molecules of alkanoyl halide to give trialkylcarbinols of 2-hydroxy-1,3-diones. When aliphatic, unbranched alkanoyl chlorides are used, this new coupling reaction provides trimeric products as the main reaction products. Tetrahydropyran (THP) proved superior as the solvent because no ring-opening and subsequent reaction with the alkanoyl halides was observed under the reaction conditions, unlike when THF was used. Wiley-VCH Verlag GmbH, 2000.
The reduction of α-silyloxy ketones using phenyldimethylsilyllithium
Fleming, Ian,Roberts, Richard S.,Smith, Stephen C.
, p. 1215 - 1228 (2007/10/03)
Phenyldimethylsilyllithium reacts with acyloin silyl ethers RCH(OSiMe3)COR 8 to give regiodefined silyl enol ethers RCH=C(OSiMe2Ph)R 9, and hence by hydrolysis ketones RCH2COR 10. The yields can be high but are usually moderate. The mechanism of this reduction is established to involve a Brook rearrangement (Scheme 6) rather than a Peterson elimination (Scheme 1). Although the mechanism appears to be the same in each case, the stereochemistries of the silyl enol ethers 9 are opposite in sense in the aromatic series (R = Ph, Scheme 7) and the aliphatic series (R = cyclohexyl, Scheme 8), with the major aromatic silyl enol ether being the thermodynamically less stable isomer E-PhCH=C(OSiMe2Ph)Ph E-9aa, and the major aliphatic silyl enol ether being the thermodynamically more stable isomer Z-c-C6H11CH= C(OSiMe2Ph)-c-C6H11 Z-9ba. This is a consequence of anomalous anti-Felkin attack in the aromatic series. The reaction with the silyl ether ButCH(OSiMe3)COPh 13b is normal in giving Z-ButCH= C(OSiMe2Ph)Ph Z-38 (Scheme 11), but reduction of the silyl ether 8a with lithium aluminium hydride is also anti-Felkin giving with high selectivity the meso diol PhCH(OH)CH(OH)Ph 39. The reaction between Phenyldimethylsilyllithium and the acyloin silyl ether 8d (R = But) does not give the ketone ButCH2COBut, but gives instead the anti-Felkin meso diol ButCHOHCHOHBut 40 also with high selectivity (Scheme 12). Silyllithium and some related reagents react with trifluoromethyl ketones 46 and 48 to give α,α-difluoro silyl enol ethers 47 and 49 (Scheme 14).
Preparation and reactions of samarium diiodide in nitriles
Hamann, Beatrice,Namy, Jean-Louis,Kagan, Henri B.
, p. 14225 - 14234 (2007/10/03)
Samarium diiodide can be prepared from samarium metal in various nitriles. Because of its chemical inertness pivalonitrile is the most suitable solvent. Organic reactions mediated by SmI2 are slower than in THF, but selectivities are often improved. Reactions are greatly accelerated by addition of catalytic amounts of some transition metal salts.
Samarium Diiodide in Tetrahydropyran: Preparation and some Reactions in Organic Chemistry.
Namy, Jean-Louis,Colomb, Marielle,Kagan, Henri B.
, p. 1723 - 1726 (2007/10/02)
SmI2 could be readily prepared in tetrahydropyran (THP) from samarium and 1,2-diiodoethane.Reducing properties were studied, showing marked differences compared to the classical SmI2/THF system.
Synthesis of α-Ketols Mediated by Divalent Samarium Compounds
Collin, Jacqueline,Namy, Jean-Louis,Dallemer, Frederic,Kagan, Henri B.
, p. 3118 - 3122 (2007/10/02)
Coupling reactions of acid chlorides are mediated by SmI2 and SmCp2, leading to α-ketols 3.Condensation reactions of acid chlorides on aldehydes similarly product α-ketols 5; with ketones, best results are obtained with use of SmI2.Reactivities of SmI2 and SmCp2 are compared and mechanisms of the reactions discussed.Formation of an acylsamarium species is shown.
On the luminescence and photochemistry of the lower excited electronic states of some acyclic 1,2-diketones
Sarphatie, Louis A.,Verheijdt, Paul L.,Cerfontain, Hans
, p. 9 - 13 (2007/10/02)
The absorption and luminescence spectra of number of acyclic 1,2-diketones have been determined, viz. of 2,3-butanedione, 2,2,5,5-tetramethyl-3,4-hexanedione, some dicycloalkyl and of cyclopropyl- and phenyl-substituted 1,2-diketones.For the 1,2-diketones without conjugating substituents, the time-averaged ground state dihedral angles between the two carbonyl group (Φ) have been estimated from the positions of the long-wavelength UV adsorption band.The variation in the fluorescence transition energy with the ground-state dihedral angle Φ is only small, viz. 1500 cm-1, on varying Φ from 0 to 180 degree.The difference between the fluorescence and phosphorescence transition energies is independent of the ground state Φ.The results show that the 1,2-diketones emit from excited states with coplanar diketo geometry.The λ 403 nmn photochemistry of 2,2,5,5-tetramethyl-3,4-hexanedione (2) and dicyclopentyl- (6) and dicyclohexyl-ethanedione (7) has been studied in some detail.The yields of the 2-hydroxycyclo-butanone products (14) formed by a Norris type II process of the triplet-excited 1,2-diketone, decrease in the substrate order 2 > 6 >> 7; an explanation for this order is proposed.
REDUCTIVE COUPLING OF S-(2-PYRIDYL) ALIPHATIC THIOATES BY USE OF BIS(1,5-CYCLOOCTADIENE)NICKEL
Onaka, Makoto,Matsuoka, Yoshio,Mukaiyama, Teruaki
, p. 905 - 906 (2007/10/02)
S-(2-Pyridyl) aliphatic thioates are reductively dimerized to give α-diketones and α-hydroxy ketones on treatment with bis(1,5-cyclooctadiene)nickel at 40 deg C.
