Detail of "12289-94-0"

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Ruthenium-catalyzed anti-Markovnikov hydroamination of vinylarenes

Ruthenium-catalyzed anti-Markovnikov hydroamination of vinylarenes. Utsunomiya, Masaru; Hartwig, John F.In this study，12289-94-0 is also used. (Department of Chemistry, Yale University, New Haven, CT 06520-8107, USA). Journal of the American Chemical Society, 126(9), 2702-2703 (English) 2004 American Chemical Society. CODEN: JACSAT. ISSN: 0002-7863. DOCUMENT TYPE: Journal CA Section: 28 (Heterocyclic Compounds (More Than One Hetero Atom)) Section cross-reference(s): 25 A ruthenium-catalyzed intermol., anti-Markovnikov hydroamination of vinylarenes with secondary aliph. and benzylic amines is reported. The combination of Ru(cod)(2-methylallyl)2, 1,5-bis(diphenylphosphino)pentane, and triflic acid was the most effective catalyst of those tested. Control reactions conducted without ligand or acid did not form the amine. The reaction of morpholine, piperidine, 4-phenylpiperazine, 4-Boc-piperazine, 4-piperidone ethylene ketal, and tetrahydroisoquinoline with styrene, in the presence of a catalytic amt. of ruthenium catalyst, gave b-phenethylamines, e.g., I, in good yields, with excellent regioselectivity, and without enamine side products. Acyclic amines such as N-hexylmethylamine and N-benzylmethylamine reacted with styrene to give the corresponding phenethylamines in moderate yields. Alkyl-, methoxy-, and trifluoromethyl-substituted styrenes reacted with morpholine in the presence of the ruthenium catalyst, or a related catalyst contg. 1,1'-bis(diisopropylphosphino)ferrocene as ligand, to give the corresponding products in good yields. Hydroamination of a-methylstyrene was obsd. with a homogeneous transition metal catalyst. Preliminary mechanistic studies showed that the reaction occurred by direct, irreversible, anti-Markovnikov hydroamination and that the mechanism of the ruthenium-catalyzed hydroamination is likely to be distinct from that of the reported rhodium-catalyzed reaction. .

Stereoselective synthesis of anti-b-hydroxy-a-amino acids through dynamic kinetic resolution

Stereoselective synthesis of anti-b-hydroxy-a-amino acids through dynamic kinetic resolution. Makino, Kazuishi; Goto, Takayuki; Hiroki, Yasuhiro; Hamada, Yasumasa (Graduate School of Pharmaceutical Sciences, Chiba University, Yayoi-cho, Inage-ku, Chiba 263-8522, Japan). Angewandte Chemie, International Edition, 43(7), 882-884 (English) 2004 Wiley-VCH Verlag GmbH & Co. KGaA. CODEN: ACIEF5. ISSN: 1433-7851. DOCUMENT TYPE: Journal CA Section: 34 (Amino Acids, Peptides, and Proteins) Section cross-reference(s): 23 Nonracemic anti-a-(benzoylamino)-b-hydroxy esters I (R = Et, EtCH2, Me2CH, Me3C, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl; R1 = Me, PhCH2) are prepd. in 53-93% yields, 74-98% ee and in 42-98% de (in all but two cases >82% de) from the hydrochlorides of a-amino-b-keto esters RCOCH(NH2)CO2R1 by enantioselective hydrogenation and dynamic kinetic resoln. in the presence of a ruthenium-BINAP catalyst generated from bis[bisbenzenedichlororuthenium(II)] and (S)-BINAP; acylation with benzoyl chloride yields I.In this article, certain chemicals are used. One of their cas registry numbers is 12289-94-0 Bis[bisbenzenedichlororuthenium(II)] is a more effective catalyst precursor than (m4-1,5-COD)Ru(m3-CH2CMe:CH2)2. Solvents such as water, tert-butanol, and ethylene glycol are ineffective for the hydrogenation, while methanol, 1-propanol, 2-propanol, and dichloromethane are all effective; in some cases, the ester group must be modified to improve soly. in dichloromethane. Hydrochloride salts of a-amino-b-keto esters are effective substrates; a tosylate salt reacts well but gives product in low enantioselectivity, while the tetrafluoroborate salt of an a-amino-b-keto ester did not react. 12289-94-0 is also in the experiment. Substrates with secondary alkyl groups are effective in the hydrogenation/dynamic kinetic resoln., while aryl groups such as Ph undergo stereoselective hydrogenation to give the anti product in high yield but with almost no enantioselectivity. The a-amino-b-keto ester reactants are prepd. by either acid hydrolysis of 4-(alkoxycarbonyl)oxazoles (from isocyanoacetates and acid anhydrides), base-mediated acyl migration of N-acylglycine esters followed by acid deprotection, or acylation of a glycine ester benzophenone imine (no data); thus the hydrogenation/dynamic kinetic resoln. of a-amino-b-keto esters allows access to both enantiomers of anti a-amino-b-hydroxy acids from simple starting materials. ..