In the aldol reaction, the diastereoselectivity of the product is often dictated by the geometry of the enolate according to the Zimmerman-Traxler model. The model predicts that the Z enolate will give syn products and that E enolates will give anti products. Chiral Lewis acids allow products that defy the Zimmerman-Traxler model, and allows for control of absolute stereochemistry. Kobayashi and Horibe demonstrated this in the synthesis of dihydroxythioester derivatives, using a tin-based chiral Lewis acid.
The transition structures for reactions with both the R and S catalyst enantiomers are shown below.
Other articles related to "aldol reaction, aldol reactions, aldol, reaction, reactions":
... Examples of aldol reactions in biochemistry include the splitting of fructose-1,6-bisphosphate into dihydroxyacetone and glyceraldehyde-3-phosphate in ... isocitrate into the four-carbon succinate and the two-carbon glyoxylate via an aldol cleavage reaction ... This cleavage is very similar mechanistically to the aldolase A reaction of glycolysis ...
... The Hajos–Parrish–Eder–Sauer–Wiechert reaction in organic chemistry is a proline catalysed asymmetric Aldol reaction ... The reaction is named after its principal investigators from Hoffmann-La Roche and Schering AG ... in the 1970s the original Hajos-Parrish catalytic procedure - shown in the reaction equation - leading to the optically active bicyclic ketol as well as the Eder-Sauer-Wiechert modification leading to the ...
... transition states to catalyze alkylation reactions, such as the aldol reaction and the Pictet-Spengler reaction ... Aldol reaction The aldol reaction is a versatile reaction in synthetic organic chemistry ... Lewis acid catalyst which aids the Pd(0) catalyzed decarboxylative aldol reaction between a ketone enolate and an aldehyde ...
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“The excessive increase of anything often causes a reaction in the opposite direction.”
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