99423-48-0Relevant articles and documents
Regioselective Robinson annulation realized by the combined use of lithium enolates and aluminum tris(2,6-diphenylphenoxide) (ATPH)
Saito, Susumu,Shimada, Itsuro,Takamori, Yusuke,Tanaka, Michiaki,Maruoka, Keiji,Yamamoto, Hisashi
, p. 1671 - 1681 (1997)
Michael addition of lithium enolates derived from ketones to a variety of a, β-unsaturated ketones was realized in the presence of aluminum tris(2,6-diphenylphenoxide) (ATPH). In this reaction, ATPH can be used as a carbonyl protector of a, β-unsaturated carbonyl substrates upon complexation, which facilitates the regioselective 1,4-addition of lithium enolates to Michael acceptors. Similarly, dianions of β-dicarbonyl compounds undergo Michael addition smoothly using ATPH as an effective promoter of the reaction. Subsequent regioselective, intramolecular aldol condensation was also demonstrated, leading to bicyclic carbon ring systems. Such systems are difficult to obtain by the Robinson annulation usually performed in protic media.
The γ-alkylation of cyclic β-ketoesters via their enamine derivatives
Gravel, Denis,Labelle, Marc
, p. 1874 - 1883 (2007/10/02)
The γ-alkylation - functionalization of cyclic β-ketoesters via their enamine derivatives is discussed with particular emphasis on their preparation from β-ketoesters and their reaction with various electrophiles such as electrophilic olefins, halogenoids, anmd allylic and benzylic halides.Although the amine ring size does not appear to affect reactivity to a great extent, the reaction is very sensitive to β-ketoester ring size, with six-membered rings giving the best results.In the latter case the alkylation-functionalization is general and specific to the γ-position and therefore provides an important complement to the dianion and related methodologies.
