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• 74181-34-3 2,2,-dimethyl-1,3-dioxan-5-one 
• 100-52-7 benzaldehyde 

Relevant academic research and scientific papers

Highly diastereo- and enantioselective direct aldol reactions in water

(Chemical Equation Presented) Going green: The synthetically very important aldol reaction can proceed in water without a metal catalyst with excellent enantioselectivity. The key to the reaction is a small, synthetic organic catalyst based on trans-hydroxyproline with a siloxy group. Thus, this method is an environmentally friendly process for the synthesis of chiral molecules.

Direct asymmetric organocatalytic de novo synthesis of carbohydrates

A biomimetic organocatalytic asymmetric synthesis of carbohydrates can be accomplished by a proline catalyzed aldol reaction with the dihydroxyacetone equivalent 2,2-dimethyl-1,3-dioxan-5-one and various aldehydes. The biomimetic C3+Cn/su

Acids as proline co-catalysts in the aldol reaction of 1,3-dioxan-5-ones

Proline-catalyzed aldol addition of 2,2-dialkyl-1,3-dioxan-5-ones to aldehydes requires the presence of water, pyridinium p-toluenesulfonate or lithium chloride to proceed with high yield and high enantioselectivity. Acyclic amino acids such as alanine, phenylalanine, lysine and valine also catalyze the reaction but overall show yields and selectivities inferior to those of proline. An ester of a proline analogue shows catalytic activity in the presence of PPTS, suggesting that, in the presence of a Br?nsted acid, a free carboxyl group on the catalyst might not be critical. Georg Thieme Verlag Stuttgart.

Highly diastereo- and enantioselective direct aldol reactions of aldehydes and ketones catalyzed by siloxyproline in the presence of water

Proline-based organocatalysts have been developed for a highly enantioselective, direct aldol reaction of aldehydes and ketones in the presence of water. While several surfactant-proline combined catalysts have proved effective, proline derivatives with a hydrophobic moiety such as rraw-siloxy-L-proline and cis-siloxy-D-proline, both of which are easily prepared from the same commercially available 4-hydroxy-L-proline. have been found to be the most effective organocatalysts examined in this study, affording the aldol product with excellent diastereo- and enantioselectivities, these two catalysts generating opposite enantiomers. Water affects the selectivity, and poor results are obtained under neat reaction conditions or in dry organic solvents. More than three equivalents of water are required for the best diastereo- and enantioselectivities. while three equivalents is the recommended amount from a synthetic point of view. The reaction proceeds in the organic phase, and also proceeds in the presence of a large amount of water. The large-scale preparation of aldols with the minimal use of an organic solvent, including in the purification step. is described.

Direct asymmetric intermolecular aldol reactions catalyzed by amino acids and small peptides

In nature there are at least nineteen different acyclic amino acids that act as the building blocks of poly-peptides and proteins with different functions. Here we report that α-amino acids, β-amino acids, and chiral amines containing primary amine functions catalyze direct asymmetric intermolecular aldol reactions with high enantio-selectivities. Moreover, the amino acids can be combined into highly modular natural and unusual small peptides that also catalyze direct asymmetric intermolecular aldol reactions with high stereoselectivities, to furnish the corre sponding aldol products with up to > 99% ee. Simple amino acids and small peptides can thus catalyze asymmetric aldol reactions with stereoselectivities matching those of natural enzymes that have evolved over billions of years. A small amount of water accelerates the asymmetric aldol reactions catalyzed by amino acids and small peptides, and also increases their stereoselectivities. Notably, small peptides and amino acid tetrazoles were able to catalyze direct asymmetric aldol reactions with high enantioselectivities in water, while the parent amino acids, in stark contrast, furnished nearly racemic products. These results suggest that the prebiotic oligomerization of amino acids to peptides may plausibly have been a link in the evolution of the homochirality of sugars. The mechanism and stereochemistry of the reactions are also discussed.