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Problematic electrophiles

Other problematic electrophiles are 2-(acylamino)ethyl halides and related compounds. Although numerous successful nucleophilic substitutions with such substrates have been described in the literature, occasionally a side reaction becomes dominant. If the leaving group is hard or if the reaction conditions chosen are conducive to the formation of carbocations, intramolecular O-alkylation of the electrophile will lead to the formation of oxazolines (Scheme 4.40). This cyclization can sometimes be avoided by choosing a softer leaving group. [Pg.86]

Sufficient reactivity towards the added electrophiles below the temperatures of carbanion decomposition or racemization. Usually, aldehydes, methyl iodide, allylic and benzylic bromides, and trialkylsilyl chlorides are the least problematic electrophiles in this context... [Pg.64]


See other pages where Problematic electrophiles is mentioned: [Pg.59]    [Pg.60]    [Pg.62]    [Pg.64]    [Pg.66]    [Pg.68]    [Pg.70]    [Pg.72]    [Pg.74]    [Pg.76]    [Pg.78]    [Pg.80]    [Pg.82]    [Pg.84]    [Pg.86]    [Pg.88]    [Pg.90]    [Pg.92]    [Pg.94]    [Pg.96]    [Pg.98]    [Pg.100]    [Pg.102]    [Pg.104]    [Pg.106]    [Pg.108]    [Pg.110]    [Pg.112]    [Pg.114]    [Pg.116]    [Pg.118]    [Pg.120]    [Pg.122]    [Pg.124]    [Pg.126]    [Pg.128]    [Pg.130]    [Pg.132]    [Pg.134]    [Pg.136]    [Pg.138]    [Pg.140]    [Pg.487]   
See also in sourсe #XX -- [ Pg.59 ]




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