350032-06-3

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• 924-53-8 isopropyl glyoxalate 
• 104-94-9 4-methoxy-aniline 

Relevant academic research and scientific papers

TRANS-3,5-DISUBSTITUTEDPYRROLIDINE: ORGANOCATALYST FOR anti-MANNICH REACTIONS

A compound of Formula I is disclosed, in which R is a substituent containing a hydrogen bond-forming atom within three atoms from the ring carbon to which the substituent is bonded; X is CH2, O, S or NR1, wherein R1 is a hydrocarbyl group or an amino-protecting group having one to about 18 carbon atoms; R2 is hydrido or a hydrocarbyl group containing one to about twelve carbon atoms; and R3 is hydrido or methyl, but both R2 and R3 are not hydrido when X is CH2 A molecule of Formula I and those in which R2 and R3 can both be hydrido (Formula X) functions as a catalyst in a Mannich reaction to asymmetrically form β-aminoaldehyde or β-aminoketone diastereomeric products having two chiral centers on adjacent carbon atoms and in which the anti-diastereomers are in excess over the syn-diastereomers. Methods for carrying out those syntheses are also disclosed.

3-Pyrrolidinecarboxylic acid for direct catalytic asymmetric anti-Mannich-type reactions of unmodified ketones

We report the development of direct catalytic, enantioselective, anti-selective Mannich-type reactions between unmodified ketones and α-imino esters under mild conditions. The reactions were performed using 5-10 mol % of (R)-3-pyrrolidinecarboxylic or (R)-β-proline as catalyst in an environmentally benign solvent, 2-PrOH, at room temperature. The anti-Mannich products were obtained in good yields with high diastereo- and enantioselectivities (up to anti/syn >99:1, 99% ee). While (3R,5R)-5-methyl-3-pyrrolidinecarboxylic acid is an excellent catalyst for the anti-Mannich-type reactions of aldehydes, it did not efficiently catalyze the corresponding Mannich-type reactions of ketones; (R)-3-pyrrolidinecarboxylic acid did efficiently catalyze the Mannich-type reactions of ketones. (S)-Proline or (S)-2-pyrrolidinecarboxylic acid has been reported to catalyze the Mannich-type reactions of ketones to afford the syn-products. Thus, the position of the carboxylic acid group on the pyrrolidine ring directs the stereoselection of the catalyzed reaction, providing either syn- or anti-Mannich products. Copyright

Mechanism of palladium complex-catalyzed enantioselective Mannich-type reaction: Characterization of a novel binuclear palladium enolate complex

Studies on the enantioselective addition of enol silyl ethers to imines catalyzed by optically active palladium diaquo complexes 3 or binuclear palladium μ-hydroxo complex 4 are described, with particular focus on the mechanistic aspects. Asymmetric induction in the reaction using [Pd((R)-binap)(H2O)2]2+(BP4 -)2 (3a) was quite sensitive to the reaction conditions, suggesting unfavorable effects of HBF4 generated from 3a in situ. Novel optically active binuclear μ-hydroxo complexes [{Pd((R)-binap)(μ-OH)}2]2+(BF4 -)2 (4a), [{Pd-((R)-tol-binap)(μ-OH)}2]2+(BF4 -)2 (4b), [{Pd((R)-binap)(μ-OH)}2]2+(TfO-)2 (4c), and [{Pd((R)-tol-binap)(μ-OH)}2]2+(TfO-) 2 (4d) were prepared and were found to be better catalysts for the asymmetric Mannich-type reaction. Benzoylalanine derivatives 5 were obtained in excellent chemical and optical yields (up to 90% ee). Mechanistic studies using 1H NMR and electrospray ionization mass spectrometry indicated that a unique binuclear palladium-sandwiched enolate 12 was involved in the reaction of enol silyl ether 1 with imine 2 catalyzed by 4.