86370-67-4Relevant academic research and scientific papers
Preparation of N-Silyl-enamines from α-Silyl Carbanions and Aromatic Nitriles
Konakahara, Takeo,Kurosaki, Yoshihiro
, p. 1068 - 1086 (2007/10/02)
The preparations of seven N-silyl-enamines (1a) - (1g) and their chemical behaviour are reported.Lithiated 4-(trimethylsilylmethyl)pyridine (2b) easily reacted with benzonitrile (4a) in tetrahydrofuran to give only (E)-1-phenyl-2-(4-pyridyl)-1-(trimethylsilylamino)ethene (1b) in 90percent yield.On the other hand, lithiated t-butyl trimethylsilylacetate (2c) did not react with (4a) at all, but reacted readily with 2- or 4-cyanopyridines, (4b) or (4c), and scarcely at all reacted with 3-cyanopyridine (4d) to give the corresponding t-butyl (Z)-3-trimethylsilylamino-3-pyridylpropenoates (1c), (1d), and (1e) in 68, 75, and 4percent yields, respectively.The reaction of 3-methyl-5-(trimethylsilylmethyl)isoxazole (2d) with the nitriles (4a) or (4b) gave the corresponding N-silyl-enamine (1g) or the desilylated enamines (5b,c), which were unstable and were readily hydrolyzed to the corresponding ketones (6a) or (6b).
Stereoselective Synthesis of trans-2-Aryl-3-(2-pyridyl)aziridines from an α-Silyl Carbanion
Konakahara, Takeo,Matsuki, Masayuki,Sugimoto, Shinji,Sato, Kenji
, p. 1489 - 1494 (2007/10/02)
Five para-substituted benzaldehyde oxime O-methyl ethers (3) reacted with 2-(trimethylsilylmethyl)pyridine (1) in the presence of lithium di-isopropylamide (LDA) in tetrahydrofuran to give the corresponding trans-2-aryl-3-(2-pyridyl)aziridines (4) in high yield (80, 85, 60, 58, and 74percent, respectively), with small amounts of (Z)-1-amino-1-aryl-2-(2-pyridyl)ethenes (5), and N',N'-di-isopropylbenzamidines (7) as byproducts.The yields of compounds (4) and (5) and their ratio were considerably influenced by experimental conditions (especially molar ratio and the addition method of the reactants).When treated with LDA, compounds (3) were quantitatively converted into benzonitriles, which reacted with anion (2) to give enamines (5) after elimination of a trimethylsilyl group from the corresponding N-trimethylsilyl derivatives, or with additional LDA to give the benzamidine (7); aziridines (4) were not transformed into enamines (5) by the action of LDA.On the basis of these results, a reaction mechanism has been discussed for the formation of compounds (4).
Reaction Mechanism of 2-(Trimethylsilyl)pyridine with Benzonitrile
Konakahara, Takeo,Sato, Kenji
, p. 1241 - 1242 (2007/10/02)
The mechanism of the reaction of lithiated 2-(trimethylsilylmethyl)pyridine with benzonitrile is discussed.The reaction proceeds through (E) and (Z)-1-phenyl-2-(2-pyridyl)-1-(trimethylsilylamino)ethene, which are quantitatively converted to 2-phenacylpyridine by acidic hydrolysis.
