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Chemoselectivity nitrogen substituent

In addition to the influence of the catalyst, it has recently been demonstrated that the chemoselectivity for the intermolecular C(sp )—H amination can also be fine-tuned by the nitrogen substituent. As mentioned above, the intermolecular reaction favors secondary benzyhc C—H bonds over tertiary positions, a reversed reactivity scale when compared to the intramolecular... [Pg.95]

The chemoselective isomerization of secondary amide-substituted oxetanes 535 in the presence of Lewis acids gave 5-hydroxymethyl-5,6-dihydro-47/-l,3-oxazines 536 in moderate to fairly good yields (Equation 63). The isomerization was dependent on the substituent on the amide nitrogen atom, since tertiary amide analogs of 535 afforded dioxazabicyclo[2.2.2]octane derivatives under similar conditions <1998CC43, 2002T7049>. [Pg.442]

Isatins and derivatives can suffer nucleophilic attack at positions C-2 and/or C-3. The chemoselectivity of these reactions depends on the nature of the nucleophile, on the nature of the substituents attached to the isatin nucleus, and especially of those bonded to the nitrogen atom, as well as upon the solvent and temperature employed. The initial products obtained can suffer further reaction in the presence of a second nucleophilic group to give cyclization products. For didactic reasons, these reactions have been sorted by the nature of the nucleophile. [Pg.41]


See other pages where Chemoselectivity nitrogen substituent is mentioned: [Pg.69]    [Pg.112]    [Pg.205]    [Pg.165]    [Pg.182]    [Pg.81]    [Pg.69]    [Pg.130]    [Pg.47]    [Pg.649]    [Pg.149]    [Pg.155]    [Pg.339]   
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