2- Aminoalcohols ketones, synthesis with

Sulfuric acid (s. a. under FeSOJ 2-Aminoalcohols from ketones via enoxysilanes and a-siloxynitriles Synthesis with addition of 1 C-atom... 

Intermolecular coupling between ketones and 0-methyl oximes, hydrazones, and nitrones occurs during reduction at a tin cathode in isopropanol [59]. The reaction with O-methyloxinies is a convenient synthesis of 2-aminoalcohols XVI. It is not clear in these reactions which of the functions, C=N or CO, is reduced first to generate the species active toward the coupling reaction. 

The heterocyclic systems of 1,3-oxazinium ions are widely used in the organic synthesis . Thus, 5,6-dihydro-4/f-l,3-oxazines 40, being a cyclic derivative of 1,2-aminoalcohols, can serve as Cj-synthones for the preparation of aldehydes, ketones and carboxylic acids . The 47/-l,3-oxazines 47 can undergo oxidative dehydrogenation by treatment with the trityl salts or benzoquinone to form the 3-azapyrylium salts 48, which then give various jV-acylenamine derivatives 49-52 by reaction with water or with active methylene comjKJunds (equation 18) . 

NbCI3-(DME) and NbCI4(THF)2 catalysts in the synthesis of Vic diamines, 2-aminoalcohols or 2,3-disubstituted-1-naphthols by coupling of imines, imines with ketones or dialdehydes acetylenes... 

The indium-mediated allylation of trifluoroacetaldehyde hydrate (R = H) or trifluoroacetaldehyde ethyl hemiacetal (R = Et) with an allyl bromide in water yielded a-trifluoromethylated alcohols (Eq. 8.56). Lanthanide triflate-promoted indium-mediated allylation of aminoaldehyde in aqueous media generated P-aminoalcohols stereoselectively. Indium-mediated intramolecular carbocyclization in aqueous media generated fused a-methylene-y-butyrolactones (Eq. 8.57). Forsythe and co-workers applied the indium-mediated allylation in the synthesis of an advanced intermediate for azaspiracids (Eq. 8.58). Other potentially reactive functionalities such as azide, enone, and ketone did not compete with aldehyde for the reaction with the in situ-generated organo-indium intermediate. 

The addition of nucleophiles to carbonyl groups is a fundamental process in organic synthesis. The addition of diethylzinc to aldehydes occurs with high ee in the presence of a wide range of aminoalcohol ligands and also titanium-based Lewis acids. This methodology has recently been extended to the enantioselective addition of alkenyl, alkynyl and arylzincs and also to the more challenging addition to ketones. 

Toward this end, a Fischer indole synthesis employing 4-carbethoxycyclo-hexanone (212) and phenyl hydrazine in warm acetic acid was followed by reduction of the resulting indole with lithium aluminum hydride to fomish hydroxymethyltetrahydrocarbazole 213. Alcohol activation with tosyl chloride and subsequent displacement of the tosylate with cyanide yielded nitrile 214. Oxidation with periodic add in methanol then formed ketone 215. Reduction of both the nitrile and carbonyl moieties was next achieved using lithium aluminum hydride in a mixture of THF and glyme at reflux to furnish aminoalcohol 216. A thermal dehydrative cyclization via heating this product in o-dichlorobenzene at reflux then led to 1,3-(iminoethano)carbazole 83. 

In 2003, Barbas and coworkers described a one-pot synthesis of functionalized P-aminoalcohols from aldehydes, acetone, and dibenzyl azodicarboxylate [2], This enzyme-like direct asymmetric assembly process was catalyzed with 20 mol% of L-proline (l-Pto) and provided the optically active products 1. This was the first example of an assembly reaction that used directly both an aldehyde and a ketone as donors in a single vessel. The success of the assembly reaction can be attributed to the higher reactivity of aldehydes over ketones in the L-Pro-catalyzed a-amination. The reaction of propionaldehyde, acetone, and dibenzyl azodicarboxylate in acetonitrile produced the expected aminoalcohol 1 in 85% yield (Scheme 12.1). The two diastereomers were obtained with an anti/syn ratio of 54 46 and with an enantioselectivity of >99% for the anti product. The authors explored the scope of the assembly reaction using various aldehydic donors, and this transformation was applied to the expedient synthesis of a potent renin inhibitor. 

The Henry reaction, or nitroaldo reaction, is one of the classic carbon-chain formation methods utilized in organic synthesis. It involves the condensation of nitroalkanes with aldehydes or ketones in the presence of bases (often catalytic amount) to afford the mixtures of diastereomeric 2-nitroalcohols, which in turn can be converted into other useful synthetic intermediates, such as 2-aminoalcohols, a-hydroxyketones, homologous ketones, and perhaps most importantly, nitroalkenes through various functional transformations. 

Trimethylsilyl [ C]cyanide is conveniently accessible from trimethylsilyl chloride, Na CN and Nal in the presence of lutidine or pyridine ". In carbon-14 synthesis it is normally generated in situ and used immediately in subsequent Lewis acid catalyzed chemical transformations. It is useful for some reactions in which alkah metal [ " C]cyanides normally fail, such as cyanide addition to acetals and aromatic and heteroaromatic aldehydes and ketones. Examples include the Znl2-catalyzed addition of TMS " CN to 2-furaldehyde followed by hydride reduction of the resultant silylated cyanohydrin to the aminoalcohol 96 " and the SnCLj-catalyzed formation of D-[l- " C]allonitrile 98, obtained from reaction of TMS " CN to the 0-acetylated hemiacetal 97 (Figure 7.26). Subsequent addition of H2Se to the nitrile group, cyclocondensation of the intermediate selenoamide in situ with ethyl bromopymvate and deprotection yielded 99, precursor to [2- " C]CI-935, a compound with... 

Synthesis of 1,2-aminoalcohols via cross-coupling of imines with ketones or aldehydes can be achieved using TifOPr-r /c-CsHgMgCl in Et20, although some ketones form cm-2,3-dialkyl aziridines predominantly. ... 

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