Ketones alkyl, reduction

This procedure illustrates a general method for preparing aromatic hydrocarbons by the tandem alkylation-reduction of aromatic ketones and aldehydes.2 Additional examples are given in Table I. 

In a total synthesis of inhibitors of this kind, the following methods have so far been employed successfully (a) reaction of a cyclohexenyl halide with an amine, (b) coupling of an amine with an epoxide, and (c) condensation of an amine with ketone and reduction of the resulting Schiff base (reductive alkylation of an amino sugar). 

Deuterium-labeled organosilicon hydride alkene to alkane reductions, 34 disubstituted alkenes, 37-38 alkyl halide reduction, 29-31 Diastereoselectivity, ketone-alcohol reduction, 76-79... 

S ilylation-intramolecular reduction, ketone-alcohol reduction, 78-79 Single-electron transfer (SET) process, alkyl halides and triflate reduction to alkanes, 28-31... 

Ketone dineopentyl-, preparation of, 54, 97 Ketone, heptyl phenyl, 53, 78 Ketones, alkylation of, 54, 48 Clemmensen reduction of, 53,... 

Catalytic processes based on the use of electrogenerated nickel(O) bipyridine complexes have been a prominent theme in the laboratories of Nedelec, Perichon, and Troupel some of the more recent work has involved the following (1) cross-coupling of aryl halides with ethyl chloroacetate [143], with activated olefins [144], and with activated alkyl halides [145], (2) coupling of organic halides with carbon monoxide to form ketones [146], (3) coupling of a-chloroketones with aryl halides to give O -arylated ketones [147], and (4) formation of ketones via reduction of a mixture of a benzyl or alkyl halide with a metal carbonyl [148]. 

Reduction = gain of electrons. Alkene, alkyne, aldehydes, ketones, alkyl halides, nitriles, carhoxylic acid and its derivatives, and benzene and its derivatives. 

Ruoho and Rong have descnbed a shorter route to salmeterol (Scheme 4). Friedel-Crafts acylation of salicylaldehyde (16) with bromoacetyl bromide in the presence of aluminum chloride gave the acetophenone 17. Alkylation of amine 18 with bromoacetyl 17 in refluxing acetonitrile gave the ketone 19. Reduction of 19 with sodium borohydride in methanol followed by catalytic hydrogenolysis of the benzyl group over 10% Pd/C gave salmeterol (2). 

The quaternary salts of ketals of 4-pyridyl alkyl and aryl ketones undergo reduction with sodium borohydride to give the expected 1,2,3,6-tetrahydropyridines.47" Reduction of an analogous ketal of a quaternary salt of a 3-pyridyl ketone led to rupture of the ketal ring.476... 

The reactions between triaUtylaluminum, R3AI, and carbonyl-containing species have been the subject of intensive study over many years . These reactions may result in adduct formation, alkylation, reduction or enolate formation, depending on the nature of the ketone and also the alkyl group attached to aluminum (equation 8). Rather surprisingly, there have been relatively few studies on mechanistic and structural aspects of enolization mediated by organoaluminum compounds. In part, this is due to the reported difficulty in the isolation and structural identification of aluminum enolates. ... 

Asymmetric Reduction of Ketones. Alkyl phenyl ketones can be asymmetrically reduced to the corresponding alcohol using Sodium Borohydride under phase-transfer conditions in the presence of a catalytic amount of QUIBEC (eq 13). The results indicate that the asymmetric reduction is due to the rigidity of the catalyst as well as the (3-position of the hydroxyl group on the quinine molecule. The asymmetric induction is much lower with a y-hydroxyl group. ... 

A much more highly diastereoselective process results when alkenic 3-keto ester and 3-ketoamide substrates can be utilized in the ketone-alkene reductive coupling process. Both electron deficient and unactivated alkenes can be utilized in the reaction (equations 65 and 66). In such examples, one can take advantage of chelation to control the relative stereochemistry about the developing hydroxy and car-boxylate stereocenters. Favorable secondary orbital interactions between the developing methylene radical center and the alkyl group of the ketyl,and/or electrostatic interactions in the transition state account for stereochemical control at the third stereocenter. 

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