Direct Amino Acid-Catalyzed Asymmetric Desymmetrization of meso-Compounds: Tandem Aminoxylation/O−N Bond Heterolysis Reactions
摘要:
A practical organocatalytic process for the synthesis of optically active, highly substituted (x-hydroxy-ketones was achieved through asymmetric desymmetrization (ADS) of prochiral ketones. The ADS and O-N bond reduction reaction of prochiral ketone with nitrosobenzene in the presence of a catalytic amount of chiral amine or amino acid produced the tandem ADS/O-N bond reduced products as single diastereomers with good yields and excellent enantiomeric excesses.
Development of drug intermediates by using direct organocatalytic multi-component reactions
作者:Dhevalapally B. Ramachary、M. Kishor、G. Babul Reddy
DOI:10.1039/b602696f
日期:——
Novel, economic and environmentally friendly one-pot three-component Knoevenagel/hydrogenation (K/H) and four-component Knoevenagel/hydrogenation/alkylation (K/H/A) reactions of ketones, CH-acids, dihydropyridines and alkyl halides using proline and proline/metal carbonate catalysis, respectively, have been developed. Many of the products of these K/H and K/H/A reactions have direct applications in pharmaceutical chemistry.
Development of Pharmaceutical Drugs, Drug Intermediates and Ingredients by Using Direct Organo-Click Reactions
作者:Dhevalapally B. Ramachary、Mamillapalli Kishor、Y. Vijayendar Reddy
DOI:10.1002/ejoc.200701014
日期:2008.2
two-carbon homologation through cascade O/H/H reactions of aldehydes 1, Meldrum's acid (3c), Hantzsch ester (4) and acetic acid/triethylamine in ethanol has been demonstrated. Additionally, we have developed a green synthesis of the highly substituted 1,2,3-triazole 17 from simple substrates through a two-step combination of olefination/hydrogenation/alkylation and Huisgen cycloaddition reaction sequences
A new domino autocatalytic reaction leading to polyfunctionalized spiro[5.5]undecanes and dispiro[4.2.5.2]pentadecanes
作者:Bo Jiang、Wen-Juan Hao、Jin-Peng Zhang、Shu-Jiang Tu、Feng Shi
DOI:10.1039/b822645h
日期:——
A new domino autocatalytic reaction of imines with Meldrum's acid was described. In this reaction, a series of polycyclic spiro[5.5]undecane-1,5,9-trione and dispiro[4.2.5.2]pentadecane-9,13-dione derivatives, with remarkable diastereoselectivity, were successfully synthesized in acidic condition, and up to six new bonds were formed accompanied by the CN bond cleavage of the imines and the decomposition of Meldrum's acid, with by-product of acetohydrazide as a novel autocatalyst.
Towards Organo-Click Chemistry: Development of Organocatalytic Multicomponent Reactions Through Combinations of Aldol, Wittig, Knoevenagel, Michael, Diels-Alder and Huisgen Cycloaddition Reactions
作者:Dhevalapally B. Ramachary、Carlos F. Barbas
DOI:10.1002/chem.200400597
日期:2004.11.5
copper(I) for catalyzing multicomponent reactions (MCRs). We aimed to prepare both diene and dienophiles simultaneously, under very mild and environmentally friendly conditions, thus giving the constituents for a stereocontrolled Diels-Alder reaction, which in turn yields compounds 4 to 8. A diversity-oriented synthesis of polysubstituted spirotriones 4 to 6 were assembled from simple substrates like
Sodium Acetate Catalyzed Multicomponent Cyclization of Aromatic Aldehydes, Acetone and Meldrum Acid
作者:Lin An、Feng Yang、Rong Yao、Chaoguo Yan
DOI:10.1002/cjoc.201190020
日期:2010.12
The sodium acetate catalyzed three‐component reaction of aromatic aldehyde, acetone and Meldrum acid or spirolactone at room temperature gave stereospecific 7,11‐cis‐diaryl‐2,4‐dioxaspiro[5,5]undecane‐1,5,9‐triones in a very efficient manner.