Synthesis 2-aminoalcohols from ketone

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

L. R. Reddy, N. Bhanumathi, K. R. Rao, D5mamic kinetic asymmetric synthesis of j8-aminoalcohols from racemic epoxides in cyclodextrin complexes under solid state conditions, Chem. Commun., 2000, 2321-2322, M. A. Reddy, N. Bhanumathi, K. R. Rao, Asymmetric synthesis of 2-azido-l-arylethanols from azido aryl ketone-j3-cyclodextrin complexes and sodium borohydride in water, Chem. Commun., 2001, 1974-1975. 

For the last two decades, the use of the platinum- or rhodium-catalyzed intramolecular hydrosilylation/Tamao-Fleming oxidation sequence has been well recognized as a powerful method for the stereoselective synthesis of various structurally diverse alcohols (1,3-diols, 2-alkoxy-l,3-diols, and 2-aminoalcohols) and ketone derivatives (/3-hydroxyketones, y-hydroxyketones, o, /3-dihydroxyketones, and a,y-dihydroxyketones) from simple and readily available starting materials such as substituted allyl or propargyl alcohols and their homologues (4,177). Selected applications are presented in equations (24-26). 

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. 

It should be noted that there are several other means by which the key a-aminocarbonyl intermediates of the Gutknecht synthesis may be prepared besides by the reduction of a-oximino ketones. The oxidation of a-aminoalcohols, reduction of a-amino acids and their derivatives, hydrolysis of a-acetamido ketones formed from a-amino acids and acetic anhydride by the Dakin-West reaction, and the reduction of a-azido, a-diazo, and a-nitro ketones all lead to dihydropyrazines by way of a-amino ketones. The Gastaldi synthesis provides an alternate use of a-oximino ketones, to afford dicyano pyrazines. ... 

The pioneering work from Itsuno group [11-14] on stoichiometric 1,2-aminoalcohol-borane complex-mediated borane reduction of ketones led to the discovery of well-defined oxazaborolidine catalyzed asymmetric reduction by Corey and coworkers [15-18]. Known as Corey-Bakshi-Shibata reaction, or CBS reduction, this reaction has become a standard method for making chiral secondary alcohols for complex molecule synthesis [19]. The generally accepted mechanism of this reaction is shown in Fig. 2. Coordination of the electrophilic reductant BH3 to the nitrogen atom of... 

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... 

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