- Silylamines in Organic Synthesis. Reactivity of N,N-Bis(silyl) Enamines toward Electrophiles. A Route to Substituted 2-Aza-1,3-butadienes and Pyridines
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N,N-Bis(silyl) enamines appeared to be weak nucleophilic reagents and exhibited a very low reactivity toward electrophiles.However, in the presence of a nucleophilic catalyst, nucleophilic activation of the silicon-nitrogen bond was observed.Under fluoride ion catalysis (TBAF or CsF), N,N-bis(silyl) enamines reacted with carbonyl compounds to give substituted 2-aza-1,3-butadienes.Good yields were obtained in reactions with aromatic aldehydes or ketones.In the case of aliphatic carbonyl compounds, 2-aza 1,3-dienes were only formed in moderate yields.Interestingly, enamidines were easily obtained in high yields upon reactions of dimethylformamide in the presence of MeONa as catalyst.The reaction of aromatic α,β-unsaturated ketones gave 2-aza 1,3,5-trienes, which were not isolated but underwent an intramolecular cycloaddition reaction with regioselective formation of substituted 2,4-diarylpyridines.
- Corriu, Robert J. P.,Moreau, Joel J. E.,Pataud-Sat, Magali
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p. 2878 - 2884
(2007/10/02)
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