5037-22-9Relevant academic research and scientific papers
Nickel-Catalyzed Selective Reduction of Carboxylic Acids to Aldehydes
Iosub, Andrei V.,Morav?ík, ?tefan,Wallentin, Carl-Johan,Bergman, Joakim
supporting information, p. 7804 - 7808 (2019/10/14)
The direct reduction of carboxylic acids to aldehydes is a fundamental transformation in organic synthesis. The combination of an air-stable Ni precatalyst, dimethyl dicarbonate as an activator, and silane reductant effects this reduction for a wide variety of substrates, including pharmaceutically relevant structures, in good yields and with no overreduction to alcohols. Moreover, this methodology is scalable, allows access to deuterated aldehydes, and is also compatible with one-pot utilization of the aldehyde products.
Transformation of Carbonyl Compounds into Homologous Alkynes under Neutral Conditions: Fragmentation of Tetrazoles Derived from Cyanophosphates
Yoneyama, Hiroki,Numata, Masahiro,Uemura, Kenji,Usami, Yoshihide,Harusawa, Shinya
, p. 5538 - 5556 (2017/06/07)
Cyanophosphates (CPs) can be easily prepared from either ketones or aldehydes, and their reaction with NaN3-Et3N·HCl results in the formation of azidotetrazoles. Under microwave irradiation, successive fragmentation of the azidotetrazoles generates alkylidene carbenes that undergo [1,2]-rearrangement and are transformed into homologous alkynes. Treatment of ketone-derived CPs with TMSN3 and Bu2SnO as catalyst in toluene at reflux directly yields the corresponding internal alkynes, whereas the reaction of aldehyde-derived CPs with NaN3-Et3N·HCl in THF at reflux or TMSN3-Bu2SnO (cat.) in toluene at reflux provides homologous terminal alkynes in good yields. These reactions take place under neutral conditions and can be successfully extended to obtain alkynes that are not usually accessible from the corresponding carbonyl compounds by the Ohira-Bestmann or Shioiri procedures, which require basic conditions.
The Retro-Hydroformylation Reaction
Kusumoto, Shuhei,Tatsuki, Toshiumi,Nozaki, Kyoko
supporting information, p. 8458 - 8461 (2015/11/27)
Hydroformylation, a reaction that adds carbon monoxide and dihydrogen across an unsaturated carbon-carbon multiple bond, has been widely employed in the chemical industry since its discovery in 1938. In contrast, the reverse reaction, retro-hydroformylation, has seldom been studied. The retro-hydroformylation reaction of an aldehyde into an alkene and synthesis gas (a mixture of carbon monoxide and dihydrogen) in the presence of a cyclopentadienyl iridium catalyst is now reported. Aliphatic aldehydes were converted into the corresponding alkenes in up to 91 % yield with concomitant release of carbon monoxide and dihydrogen. Mechanistic control experiments indicated that the reaction proceeds by retro-hydroformylation and not by a sequential decarbonylation-dehydrogenation or dehydrogenation-decarbonylation process.
Photochemistry of Substituted Benzoylformate Esters. A Convenient Method for the Photochemical Oxidation of Alcohols
Pirrung, Michael C.,Tepper, Ronald J.
, p. 2461 - 2465 (2007/10/02)
The production of aldehydes and ketones via photochemical hydrogen atom transfer in substituted benzoylformate esters of primary and secondary alcohols has been investigated.Substituent effect studies have shown that (2,4-dimethoxybenzoyl)formate (DMBF) esters give superior performance.A divergence in the byproducts derived from the ester group (the benzaldehyde (and presumably CO) or the benzoic acid (and presumably CO2)) is observed depending on the presence of oxygen.A mechanistic rationale for the benzoic acid has been advanced based on the known trapping of intermediate 1,4-biradicals by oxygen followed by fragmentation.
Organoaluminum-catalyzed rearrangement of epoxides a facile route to the synthesis of optically active β-siloxy aldehydes
Maruoka, Keiji,Ooi, Takashi,Nagahara, Shigeru,Yamamoto, Hisashi
, p. 6983 - 6998 (2007/10/02)
A new, stereocontrolled rearrangement of epoxy silyl ethers leading to β-siloxy aldehydes has been effected with stoichiometric use of exceptionally bulky, oxygenophilic methylaluminum bis(4-bromo-2,6-di-trert-butylphenoxide) (MABR) under mild conditions. Used in combination with the Sharpless asymmetric epoxidation of allylic alcohols, this rearrangement represents a new approach to the synthesis of various optically active β-hydroxy aldehydes, useful intermediates in natural product synthesis. The modified organoaluminum reagent, MABR is also applicable to the transformation of a variety of simple epoxides to carbonyl compounds with high efficiency and selectivity. Further, the catalytic version for the rearrangement of epoxy silyl ethers as well as simple epoxides has been newly devised. The scope and limitation of this catalytic method has been clarified with various epoxy substrates.
An Efficient, Catalytic Procedure for Epoxide Rearrangement
Maruoka, Keiji,Nagahara, Shigeru,Ooi, Takashi,Yamamoto, Hisashi
, p. 5607 - 5610 (2007/10/02)
Exceptionally bulky, oxygenophilic methylaluminum bis(4-bromo-2,6-di-tert-butylphenoxide) (reagent A) can be utilized as an active catalyst for the transformation of various epoxides to carbonyl compounds with high efficiency and selectivity.
Functionalization of Saturated Hydrocarbons. 14. Further Studies on the Mechanism of Gif-Type Systems
Barton, Derek H. R.,Halley, Frank,Ozbalik, Nubar,Schmitt, Martine,Young, Esme,Balavoine, Gilbert
, p. 7144 - 7149 (2007/10/02)
The photolysis (W light) of acyl derivatives of N-hydroxy-2-thiopyridone in pyridine-acetic acid permits a study of the partioning of secondary radicals between oxygen, pyridine, and the thione function.Comparison with the GifIV oxidation system for saturated hydrocarbons confirms that radicals are not involved in oxidation at secondary positions.On the contrary, radical behavior at the tertiary position in adamantane is again established.The two recently introduced Gif-type systems, GoAggI and GoAggII, have been shown to give the same overall selectivity in attack on adamantane with the usual coupling of the tertiary radical with pyridine.
Synthesis of aldehydes by a one-carbon homologation of ketones and aldehydes via --α,β-unsaturated isocyanides
Moskal, Janusz,Leusen, Albert M. van
, p. 137 - 141 (2007/10/02)
Ketones and aldehydes react via a Wittig-Horner-Emmons reaction using diethyl(isocyanomethyl)phosphonate to form α,β-unsaturated isocyanides (4), which are either hydrolyzed as such, under acid conditions, or hydrolyzed after oxidation to α,β-unsaturated isocyanates (6) to give aldehydes containing one additional carbon atom.The scope of the reaction is demonstrated by 20 examples.
A New Synthetic Application of 1,2-Benzodithiolium Cations: Synthesis of Aldehydes by 1-Carbon Homologation of Carbonyl Compounds
Ceruti, Maurizio,Degani, Iacopo,Fochi, Rita
, p. 79 - 82 (2007/10/02)
Eleven aldehydes (6a-l) were synthesized by 1-carbon homologation of ketones and aldehydes according to the following sequence: Horner-Emmons reaction of 2-(O,O-dimethylphosphonyl)-1,3-benzodithiole (1) and various carbonyl compounds (2) to give benzo-1,4-dithiafulvenes (3); reduction with sodium borohydride and tetrafluoroboric acid-ether complex in dry acetonitrile to 1,3-benzodithioles (5); subsequent hydrolysis of these with mercury(II)oxide and aqueous tetrafluoroboric acid (35percent) in tetrahydrofuran.The procedure is simple, of wide application, and afforded pure aldehydes in good overall yields (55-88percent).
