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A-acetylenamides

A -Acetylenamide No examples 4 steps Not possible Not possible Not possible... [Pg.139]

Further progress in the hydrogenation disubstituted A-acetylenamides was made with the sterically less hindered Me-Du-PHOS-rhodium catalyst. In this system an ee value of 92 % was obtained. [5]... [Pg.54]

The strategies presented in Table 8.1 can be generalized in the following manner (1) carbanion addition to aldimine or ketimine derivatives (2) sequential amination-alkylation of aldehydes (carbanion addition to in situ formed aldimine derivatives) (3) transfer hydrogenation or hydrogenation of imines (4) reductive amination of ketones and (5) N-acetylenamide reduction. Because of the difficulty of their synthesis, a-alkyl,-alkyl substituted amines are highlighted whenever possible. [Pg.140]

The best enantioselectivities till now have been reached with the Me-BPE ligand. With this ligand a large variety of y5, -disubstituted Af-acetylenamides were hydrogenated with... [Pg.54]

Corytenchirine, found in Corydalis ochotensis Turcz. (Fumariaceae) has been prepared in the racemic form by irradiation of an 7V-acetylenamide followed by reduction of the resulting protoberberinium salt and debenzylation. ° An alternate synthesis of corytenchirine involves Mannich cyclization of the required tetrahydrobenzylisoquinoline precursor with acetaldehyde. A diastereomer of corytenchirine was also produced in this instance, but in minor amounts. (See also Sec. 19.2.1.)... [Pg.221]

See other pages where A-acetylenamides is mentioned: [Pg.139]    [Pg.52]    [Pg.54]    [Pg.139]    [Pg.52]    [Pg.54]    [Pg.140]    [Pg.146]    [Pg.150]    [Pg.152]    [Pg.140]    [Pg.146]    [Pg.150]    [Pg.152]   
See also in sourсe #XX -- [ Pg.52 ]



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