- α-Xanthylmethyl Ketones from α-Diazo ketones
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A simple and efficient method to obtain α-xanthylmethyl ketones from α-diazo ketones is described. The reaction proceeds through a protonation/nucleophilic substitution sequence in the presence of p -toluenesulfonic acid and potassium ethyl xanthogenate as the nucleophile. As α-diazo ketones can be readily synthesized from ubiquitous carboxylic acids, a broad variety of xanthates can be obtained, including examples from naturally occurring substrates.
- López-Mendoza, Pedro,Miranda, Luis D.
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p. 3777 - 3790
(2021/07/07)
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- Convenient synthesis of adamantyl-substituted β -lactams via uncatalyzed staudinger reaction
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A series of C3-position adamantyl-substituted β-lactams were synthesized via uncatalyzed Staudinger reaction between adamantylketene generated by thermal Wolff rearrangement of the corresponding diazo ketone and various imines. The stereochemical outcome of the reaction was mainly the formation of trans-products, a result attributed to a two-step mechanism leading to the most stable products.
- Liu, Mingshun,Chen, Yaqing,Fu, Nanyan
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p. 1055 - 1062
(2013/02/25)
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- New synthetic technology for the synthesis of hindered α-diazoketones via acyl mesylates
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(equation presented) A mild and reliable one-pot protocol for the elaboration of sterically demanding carboxylic acids into α-diazoketones via acyl mesylates has been developed. Aside from delineating the reaction parameters which render this strategy quite general for hindered carboxylic acids, we have directly proven the existence of the fleeting acyl mesylate group as the reactive species in these reactions and shed light onto the differing mechanisms which are operative in the activation of hindered and simple carboxylic acids with methanesulfonyl chloride.
- Nicolaou,Baran, Phil S.,Zhong, Yong-Li,Choi, Ha-Soon,Fong, Kin Chiu,He, Yun,Yoon, Won Hyung
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p. 883 - 886
(2008/02/09)
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- Oxidation of diazo compounds by dimethyl dioxirane: An extremely mild and efficient method for the preparation of labile α-oxo-aldehydes
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A novel method for the preparation of α-oxo-aldehydes by dimethyl dioxirane oxidation of α-diazoketones is described. The procedure is particularly useful when the desired compound cannot be purified by chromatography or distillation: the by-products (ace
- Ihmels,Maggini,Prato,Scorrano
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p. 6215 - 6218
(2007/10/02)
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- WOLFF RAERRANGEMENT OF (1-DIAZO-2-OXOALKYL) SILANES
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Photochemical decomposition of (1-diazo-2-oxoalkyl) silanes 6a-l results in Wolff rearrangement yielding silyl ketenes 8a-l.From (1-diazo-3,3-dimethyl-2-oxobutyl) silanes 6c-f, 2-silyl-cyclobutanones 9c-f are formed as by-products, arising from intramolecular C/H insertion of the acyl carbene intermediate.Irradiation of diazo-triisopropylsilyl-acetamide 6m yields only β-lactam 16 and γ-lactam 17.Wolff rearrangement also takes place on copper triflate catalyzed decomposition of 6a,c,l, whereas the 1-oxa-2-sila-4-cyclopentene 19 is obtained from 6f, probably as the result of SiC/H insertion of a copper carbene intermediate.
- Brueckmann, Ralf,Schneider, Klaus,Maas, Gerhardt
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p. 5517 - 5530
(2007/10/02)
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- SYNTHESIS OF SILYLDIAZOKETONES FROM LITHIUM PENTAMETHYLDISILANYLDIAZOMETHANE WITH ACID CHLORIDES
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Lithium pentamethyldisilanyldiazomethane, prepared from pentamethyldisilanyldiazomethane and lithium diisopropylamide, reacts with acid chlorides to give pentamethyldisilanyldiazoketones in good yields.
- Sekiguchi, Akira,Sato, Takashi,Ando, Wataru
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p. 1083 - 1084
(2007/10/02)
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