- Rh-Catalyzed Asymmetric Hydrogenation of 1,2-Dicyanoalkenes
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A highly efficient enantioselective hydrogenation of 1,2-dicyanoalkenes catalyzed by the complex of rhodium and f-spiroPhos has been developed. A series of 1,2-dicyanoalkenes were successfully hydrogenated to the corresponding chiral 1,2-dicyanoalkanes under mild conditions with excellent enantioselectivities (up to 98% ee). This methodology provides efficient access to the asymmetric synthesis of chiral diamines.
- Li, Meina,Kong, Duanyang,Zi, Guofu,Hou, Guohua
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p. 680 - 687
(2017/04/26)
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- Synthesis of benzoyl cyanide through aerobic photooxidation of benzyl cyanide using carbon tetrabromide as a catalyst
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We developed a synthetic method toward benzoyl cyanide through aerobic photooxidation of benzyl cyanide in the presence of carbon tetrabromide under visible light irradiation with fluorescent lamps.
- Sugiura,Tachikawa,Nagasawa,Tada,Itoh
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p. 70883 - 70886
(2015/09/08)
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- Ruthenium-Catalyzed Oxidations of Alcohols
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A combination of low-valent ruthenium complexes and peroxides such as t-BuOOH and peracids serves as efficient catalytic systems for the oxidation of aromatic and aliphatic hydroxy compounds. The utility of these methods was demonstrated by the synthesis of acyl cyanides which are versatile synthetic intermediates. The principle of the catalytic oxidations with peracids lead to the novel and efficient method for aerobic oxidation of alcohols in the presence of aldehydes. This reaction is of importance in synthetic and large scale industrial processes and from environmental points of view. The present principle will provide new chemistry of oxidative transformations of various industrially important functional materials.
- Murahashi,Naota
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p. 203 - 213
(2007/10/03)
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- Ruthenium-catalyzed oxidations for selective syntheses of ketones and acyl cyanides. Selective acylation of amino compounds with acyl cyanides
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Oxidation of alcohols to the corresponding carbonyl compounds with tert-butyl hydroperoxide in the presence of dichlorotris(triphenylphosphine)ruthenium catalyst gives the corresponding carbonyl compounds with high efficiency. This method can be applied to the oxidation of cyanohydrins to give acyl cyanides which are versatile synthetic intermediates. Acylation of amino compounds with acyl cyanides thus obtained proceeds chemoselectively. Thus, the reaction of amino alcohols with acyl cynides gives N-acylated products exclusively. In the similar N-acylation of polyamines primary amines are selectively acylated in the presence of secondary amines. These reactions are highly useful for the synthesis of spermidine and spermine alkaloids such as spermidine alkaloids such as spermidine siderophores. Dimeric cyclocoupling reaction of diacyl cyanides such as iso- and terephthaloyl cyanides with polyamines can be performed under the similar reaction conditions to give the corresponding polyazamacrocycles with high efficiency.
- Murahashi,Naota
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p. 433 - 440
(2007/10/02)
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- RUTHENIUM CATALYZED OXIDATION OF CYANOHYDRINS TO ACYL CYANIDES USEFUL REAGENTS FOR SELECTIVE N-BENZOYLATION OF AMINOALCOHOLS
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Ruthenium catalyzed oxidation of cyanohydrins with tert-butyl hydroperoxide gives the corresponding acyl cyanides in good to excellent yields.Acyl cyanides thus obtained are useful reagents for selective N-benzoylation of aminoalcohols.
- Murahashi, Shun-ichi,Naota, Takeshi,Nakajima, Nobuyuki
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p. 925 - 928
(2007/10/02)
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- A Novel Synthesis of Peptide Based on the Photochemistry of 5-Azido-1,3,4-oxadiazoles
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A novel approach to the synthesis of peptides is described.Various N-protected amino acid hydrazides 17 were converted to the salts 18 by condensation with carbon disulfide in methanolic potassium hydroxide.Thermal cyclization of 18 to the heterocycles 19 was followed by reaction with methyl iodide to yield the sulfides 20.After oxidation of 20 to the corresponding sulfones 21, the title compounds 22 were prepared by treating 21 with sodium azide.Deprotection then yielded the free bases 23.Utilization of 22 and 23 in peptide synthesis, relying on a photochemical degradation of the title heterocycle present in these compounds, is described.The scope and limitations of this new methodology are also discussed.
- Confalone, Pat N.,Woodward, Robert B.
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p. 902 - 906
(2007/10/02)
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- Reaction of Guanidinium Salts with Alkyl Bromides and Acid Chlorides
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The guanidinium salt 1a reacts with alkyl bromides 2a-g and acid chlorides 2h-k to give the nitriles 3a-g and the acyl cyanides 3h-k, respectively.Acyl isocyanates 4a,b have been obtained from the guanidinium cyanate 1d and the acid chlorides 2h,l.Reaction of the alkyl bromides 2b,c,m,n and acid chlorides 2h,l with the guanidinium thiocyanate 1e affords alkyl thiocyanates 5a-d and acyl isothiocyanates 6a,b, respectively.
- Kantlehner, Willi,Kapassakalidis, Johannis J.,Speh, Peter,Braeuner, Hans-Juergen
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p. 389 - 393
(2007/10/02)
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