169136-82-7Relevant academic research and scientific papers
Study of the asymmetric synthesis of (Z)-γ-substituted α,β- didehydroglutamates from N-alkylideneglycinates
Alvarez-Ibarra, Carlos,Csaky, Aurelio G.,Martin, M. Elena,Quiroga, M. Luz
, p. 7319 - 7330 (1999)
The synthesis of (Z)-γ-substituted-α,β-didehydroglutamates has been accomplished either starting from the glycinates 1 or the α, β- didehydroglutamates 6. In the first case, no reaction of the lithium enolates 3 was observed, and the use of the naked anions 4 was required; while in the second case, the lithium enolates 7 reacted successfully with alkyl halides to afford the target molecules.
Accessing N-Stereogenicity through a Double Aza-Michael Reaction: Mechanistic Insights
Kohrt, Sonja,Santschi, Nico,Cvengro, Jn
, p. 390 - 403 (2016/01/25)
Further development of the chemistry and applications of chiral compounds that possess configurationally stable stereogenic nitrogen atoms is hampered by the lack of efficient strategies to access such compounds in an enantiomerically pure form. Esters of propiolic acid and chiral alcohols were evaluated as cheap and readily available Michael acceptors in a diastereoselective synthesis of N-stereogenic compounds by means of a double aza-Michael conjugate addition. Diastereomeric ratios of up to 74:26 and high yields were achieved with (-)-menthyl propiolate as a substrate. Furthermore, a detailed mechanistic investigation was undertaken to shed some light on the course of this domino transformation. Kinetic studies revealed that the protic-solvent additive acts as a Bronsted acid and activates the ester toward the initial attack of the tetrahydrodiazocine partner. Conversely, acidic conditions proved unfavorable during the final cyclization step that provides the product.
Diastereoselectivity in the intermolecular Pauson-Khand reaction of chiral 2-alkynoates
Fonquerna, Silvia,Moyano, Albert,Pericas, Miquel A.,Riera, Antoni
, p. 4239 - 4254 (2007/10/02)
Chiral 2-alkynoates have been readily prepared by condensation of several cyclohexyl- or camphor-based alcohols with 2-alkynoic acids or the corresponding acid chlorides. The hexacarbonyldicobalt complexes obtained therefrom reacted with olefins to afford the corresponding Pauson-Khand cyclopentenone adducts in good yields, with high regioselectivity, and with variable degrees of diastereoselectivity. In some instances, the degree of stereocontrol is superior to that observed for alkoxyacetylenes, so that the viability of an enantioselective approach to the intermolecular Pauson-Khand reaction of electron-deficient alkynes is demonstrated for the first time.
