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Ketones, Sulfoxides, Sulfones

A large part of the usefulness of the Michael reaction in organic synthesis derives from the fact that almost any activated alkene can serve as an acceptor7—a, 3-unsaturated ketones, esters, aldehydes, amides, acids, lactones, nitriles, sulfoxides, sulfones, nitro compounds, phosphonates, phosphoranes, quinones,... [Pg.4]

Enediamine 93 undergoes an easy C-alkylation with a,/ -unsaturated ketones under comparable conditions and no cyclocondensation products are observed36. Similar C-alkylations with other electrophilic olefins such as unsaturated lactones, propenonitrile, vinyl sulfoxide, sulfone and phenylphosphonium bromide have been achieved36. All the adducts 135 exist predominantly as the imine form (see Section II.A). Treatment with organometallic reagents transforms the C-alkylated products into... [Pg.1334]

Chemiluminescence intensity is affected when dioxetane is replaced from the coordination sphere of the Eu(III) by the other ligand, such as sulfoxides, sulfones or ketones (Scheme 3). This effect allowed us to develop a chemiluminescent procedure to study equilibriums in solutions. If we know stability constant (K ) for the Eu(fod)3-DO complex, we may obtain an equilibrium constant... [Pg.145]

Moreover, by means of the method of luminescent-kinetic spectroscopy we have shown that Eu(III) ion in excited state forms more stable complex (up to two orders of magnitude) with sulfoxides, sulfones, ketones and amines then that in ground state. Since it is known that excitation of the europium is caused by electron transitions in the inner metal-centered 4f-states, our findings testify that f-electrons participate in the chemical bonding. [Pg.145]

Phase-transfer catalysis. A Polish group reported that the Wittig-Horner reaction with a-phosphoryl sulfoxides, sulfones, and sulfides could be conducted in a two-phase system (aqueous NaOH-methylene chloride) with benzyltriethyl-ammonium chloride as catalyst. Later work showed that a catalyst was not necessary because these sulfur compounds themselves can function as catalysts for phase-transfer reactions. Thus (1) is an effective catalyst for alkylation of ketones by alkyl halides in the presence of 50% aqueous NaOH. Related, but somewhat less active, catalysts are sulfones such as (2), a-disulfoxides (3), and bisphosphonates (4). [Pg.191]

Another FBC approach was developed by Knochel and co-workers to oxidize olefins, sulfides, and aldehydes to epoxides, sulfoxides, sulfones, and carboxylic acids (79). They used the Ru and Ni complexes of a perfluorinated 1,3-diketone, obtained in one step in 80 % yield by the condensation of a perfluoromethyl ester and a perfluoromethyl ketone, as catalysts for these oxidation reactions. More importantly, these Ru and Ni complexes were found to be highly soluble in perfluorocarbons (Figure 3). [Pg.178]

Oxone sulfoxidations can show appreciable diastereoselectiv-ity in appropriate cases, as demonstrated in eq 26. Enantio-selective oxidations of sulfides to sulfoxides have been achieved by buffered aqueous Oxone solutions containing bovine serum albumin (BSA) as a chiral mediator (eq 27). As little as 0.05 equiv of BSA is required and its presence discourages further oxidation of the sulfoxide to the sulfone. Oxone can be the active oxidant or reaction can be performed in the presence of acetone, trifluoroacetone, or other ketones, in which case an intermediate dioxirane is probably the actual oxidizing agent. The level of optical induction depends on structure of the sulfide and that of any added ketone. Sulfoxide products show ee values ranging from 1% to 89%, but in most examples the ee is greater than 50%. [Pg.478]

Strongly dipolar, non-HBD ketones, A/,Af-dialkyamides, nitro-compounds, sulfoxides, sulfones, pyridine. [Pg.102]

Both terminal and nonterminal acetylenes have been used. Activating groups oL to the acetylenic bond have included sulfone (131-135), sulfoxide (134), ester (28,133-139), and ketone (134,140). Whether adduct 183 Is designated as cis or trans depends on the investigators and the particular compound. If the addition reaction is carried out in aprotic solvents, the major isomer is 183 formed by cis addition (135,138,139). For example, the addition of aziridine to dimethyl acetylenedicarboxylate (182, X, Y = CO2CH3) in dimethyl sulfoxide (135) gave 75 % of a mixture containing 95 % of the Chester 185. Collapse of the intermediate zwitterion intermediate 186... [Pg.95]

Only sulfoxidation, and no elimination, occurs when the hydrochloride of 2 (R = Me) is treated with sodium periodate at room temperature.3 Ketone 4, which represents the tautomeric form of dibenzo[6,/]thiepin-10-ol, can be sulfoxidized with hydrogen peroxide at room temperature to provide sulfoxide 5 in 56% yield however, at reflux temperature oxidation occurs additionally at the carbon atom next to the oxo group and sulfone 6 is isolated in 79% yield.3... [Pg.87]

Among other methods for the preparation of alkylated ketones are (1) the Stork enamine reaction (12-18), (2) the acetoacetic ester synthesis (10-104), (3) alkylation of p-keto sulfones or sulfoxides (10-104), (4) acylation of CH3SOCH2 followed by reductive cleavage (10-119), (5) treatment of a-halo ketones with lithium dialkyl-copper reagents (10-94), and (6) treatment of a-halo ketones with trialkylboranes (10-109). [Pg.555]

Other carbanionic groups, such as acetylide ions, and ions derived from a-methylpyridines have also been used as nucleophiles. A particularly useful nucleophile is the methylsulfinyl carbanion (CH3SOCHJ), the conjugate base of DMSO, since the P-keto sulfoxide produced can easily be reduced to a methyl ketone (p. 549). The methylsulfonyl carbanion (CH3SO2CH2 ), the conjugate base of dimethyl sulfone, behaves similarly, and the product can be similarly reduced. Certain carboxylic esters, acyl halides, and DMF acylate 1,3-dithianes (see 10-10. )2008 Qxj(jatjye hydrolysis with NBS or NCS, a-keto aldehydes or a-... [Pg.572]

In contrast to a, -ethylenic ketones or even a, -ethylenic sulfones, a, ) -ethylenic sulfoxides generally are not sufficiently electrophilic to undergo successful nucleophilic j8-addition . a-Carbonyl-a, j8-ethylenic sulfoxides, however, are potent, doubly activated alkenes which undergo rapid and complete -addition of various types of nucleophiles even at — 78 °C. A brief account summarizing this area is available . The stereochemical outcome of such asymmetric conjugate additions to enantiomerically pure 2-sulfmyl 2-cycloalkenones and 2-sulfinyl-2-alkenolides has been rationalized in terms of a metal-chelated intermediate in which a metal ion locks the -carbonyl sulfoxide into a rigid conformation (36 cf. 33). In this fixed conformation, one diastereoface of the cyclic n... [Pg.838]


See other pages where Ketones, Sulfoxides, Sulfones is mentioned: [Pg.210]    [Pg.359]    [Pg.442]    [Pg.127]    [Pg.312]    [Pg.327]    [Pg.327]    [Pg.37]    [Pg.840]    [Pg.844]    [Pg.327]    [Pg.311]    [Pg.145]    [Pg.5232]    [Pg.5315]    [Pg.129]    [Pg.841]    [Pg.539]    [Pg.321]    [Pg.210]    [Pg.108]    [Pg.119]    [Pg.150]    [Pg.444]    [Pg.569]    [Pg.612]    [Pg.838]    [Pg.634]    [Pg.1230]    [Pg.612]    [Pg.442]   


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Ketones sulfonation

Sulfones ketones

Sulfones sulfoxides

Sulfones, sulfoxides, sulfonates

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