Synthesis of novel cinchona-amino acid hybrid organocatalysts for asymmetric catalysis
作者:Pedro Barrulas、Maurizio Benaglia、Anthony J. Burke
DOI:10.1016/j.tetasy.2014.05.003
日期:2014.6
Three novel subclasses of cinchonidine derivatives coupled to diverse amino acids were prepared in very good overall yield and tested in a benchmark organocatalytic aldol reaction, betweenacetone and aromatic aldehydes. These subclasses are a family of amino acid-cinchonidine (subclass A), N-formamides-cinchonidine (subclass B) and dipeptide-cinchonidine (subclass C) hybrids. Our main goal, besides
Synthesis and Catalytic Antibody Functionalization of Dendrimers
作者:Armando Córdova、Kim D. Janda
DOI:10.1021/ja001819f
日期:2001.8.1
Antibody 38C2 catalyzed a retro-aldol process upon dendritic modified aliphatic polyesters. This catalytic system was studied in detail and displayed rate enhancements, k(cat)/k(uncat), of greater than 10(6). These antibody-catalyzedreactions took place in a stepwise manner yielding partially modified aldol-dendrimers until a fully substituted aldehyde dendrimer was formed. The catalytic antibody
regio- and diastereoselectivity and enantioselectivity under ambient temperature. Significantly, the reactions accommodate the synthetically important but challenging substrates, such as linear aliphaticketones, with high regioselectivity and unprecedented syn diastereoselectivity. These results are in sharp contrast with the secondary amine mediated similar reactions wherein anti diastereoselectivity
Thiazolidine-based organocatalysts for a highly enantioselective direct aldol reaction
作者:Raoní S. Rambo、Paulo H. Schneider
DOI:10.1016/j.tetasy.2010.07.028
日期:2010.9
exhibits the highest catalytic performance working in an aqueous medium. It catalyzed the directcatalyticasymmetric intermolecular aldolreaction between unmodifiedketones and an aldehyde with excellent stereocontrol and furnished the corresponding aldol products in up to 99% ee. Compound 3a also showed excellent asymmetriccatalytic activity in the asymmetric Michael reaction (up to 99% ee).
5-(Pyrrolidine-2-yl)tetrazole: Rationale for the Increased Reactivity of the Tetrazole Analogue of Proline in Organocatalyzed Aldol Reactions
作者:Antti Hartikka、Per I. Arvidsson
DOI:10.1002/ejoc.200500470
日期:2005.10
L-proline (2) in various organocatalyzed reactions. In the organocatalyzed direct asymmetric aldol reaction, acetone was reacted with aromatic and aliphaticaldehydes to afford the resulting β-hydroxy ketones in good yields and moderate to high enantiomeric excesses. The increased reactivity of 1, as compared to 2, has been rationalized through a combined computational and NMR spectroscopicstudy. It was