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Palladium homoenolates 3-elimination

Palladium homoenolates readily undergo p-elimination to give a,P-unsaturated carbonyl compounds. Treatment of a mercurio ketone with a catalytic amount of palladium(II) in the presence of CuCh results in the formation of an enone via a 3-palladio ketone (Scheme 3). Treatment of a silyloxycyclopropane (8) with PdCh also generates in situ a palladium homoenolate which then undergoes -elimination (Scheme 3). Heating a mixture of a 3-trichlorostannyl ketone or aldehyde with DMSO results in the formation of an enone or an enal in excellent yield (Scheme 4). ... [Pg.443]

Next to the cyclopropane formation, elimination represents the simplest type of a carbon-carbon bond formation in the homoenolates. Transition metal homoenolates readily eliminate a metal hydride unit to give a,p-unsaturated carbonyl compounds. Treatment of a mercurio ketone with palladium (II) chloride results in the formation of the enone presumably via a 3-palladio ketone (Eq. (24), Table 3) [8], The reaction can be carried out with catalytic amounts of palladium (II) by using CuCl2 as an oxidant. Isomerization of the initial exomethylene derivative to the more stable endo-olefin can efficiently be retarded by addition of triethylamine to the reaction mixture. [Pg.13]

Polladium(II) chloride or its phosphine complex smoothly reacts with siloxy-cyclopropane 1 to produce acrylic ester and a palladium mirror. This reaction probably involves the formation of a chloropalladium homoenolate followed by elimination of palladium hydridochloride (Eq. (56) [56]. [Pg.28]

Transition metal cyclopropanolates underwent ring opening by P-carbon elimination to generate transition metal homoenolates. Palladium(ll)-catalyzed ring opening of substituted cyclopropanols predominantly occurred at the less substituted C-C bond to give conjugated enones (Scheme 2.31) [47]. When the reaction was performed under non-oxidative conditions, a mixture of unsaturated and saturated ketones was obtained [48]. [Pg.48]


See other pages where Palladium homoenolates 3-elimination is mentioned: [Pg.28]    [Pg.28]    [Pg.450]    [Pg.443]    [Pg.450]    [Pg.49]    [Pg.450]    [Pg.240]    [Pg.240]    [Pg.344]   


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