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Ultrasound irradiation, Michael

Cerium(IV) ammonium nitrate (CAN) has been reported to catalyse a facile and efficient aza-Michael addition of aromatic and aliphatic amines to a -unsaturated esters in the absence of solvent under ultrasound irradiation.136 a,/l-Unsaturated ketones react in aqueous solutions under these conditions but only with aliphatic (not aromatic) amines.137... [Pg.343]

Michael addition of 65 to 3-methyl-3-buten-2-one (68) in its inclusion ciystal with 2c also occuired enantioselectively. When the complex of 68 with 2c was treated with 65a-f in the presence of a catalytic amount of 66 under the same conditions as for the reaction shown in Table 15-17, products 69a-f were obtained in the optical purities shown in Table 15-18. The optical purities of 69a and 69d were relatively higher, but those of 69b and 69c were lower, whilst, in the case of 69e and 69f, enantiocontrol was not manifested [32]. It has been reported that some of the solid state organic reactions are accelerated by an irradiation of ultrasound [33]. [Pg.579]

This reaction has been extended to the Michael Addition on a,)0-unsaturated nitrile by temporarily chelating the Grignard reagent to y-hydroxy unsaturated nitrile. An alternative route involving a free-radical )0-alkylation of nonactivated carbon atoms and subsequent anionic cyclization has been developed as a complementary route of the Robinson annulation. In addition, this reaction has been modified to occur under antibody catalysis" or with the combination of a lithium enolate with aluminum tris(2,6-diphenylphenoxide). Further modifications include the Robinson annulation in supercritical C02, the reaction promoted by K2CO3 under ultrasound,and the solid-supported reaction under microwave irradiation. ... [Pg.2406]

The enantioselective Michael addition of mercapto compounds with an optically active host compound derived from 1 1 inclusion complex of 2-cyclohexenone with (-)-A derived from tartaric acid and a catalytic amount of benzyltrimethyl ammonium hydroxide on irradiation with ultrasound for 1 hr. at room temperature gave the adduct in 50-78% yield with ee 75-80% (Scheme 8). [Pg.192]


See other pages where Ultrasound irradiation, Michael is mentioned: [Pg.13]    [Pg.82]    [Pg.215]    [Pg.579]    [Pg.24]    [Pg.243]   


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Ultrasound irradiation

Ultrasound irradiation, Michael addition with

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