Abstract
A stereo-defined process has been developed for the synthesis of Mannich-type products using readily available copper sulfate or sodium chloride as catalyst. Good to excellent diastereoselectivity has been achieved for a broad array of substrates. The observed diastereoselectivity is explained on the basis of the steric interaction between the acyloxy group of the aldehyde carbon and the more hindered α-substituted enolate anion. This steric interaction helps the addition to take place through the less-hindered face to produce the anti-isomers predominantly.
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GRAPHICAL ABSTRACT
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Notes
a All reactions were carried out at room temperature.
b Isolated yield, all products were identified by comparing their NMR and IR values with those for authentic samples.[6a,6b]
c Assigned based on comparison with literature value for the coupling constants of methine proton.[6a]
a All reactions were carried out at room temperature using dichloromethane as solvent.
b Isolated yield.
c Product was identified by comparing its NMR and IR values with those for authentic samples.[6b]
a All reactions were carried out at room temperature.
b Isolated yield.
c Products were identified by comparing their NMR and IR values with those for authentic samples.[ Citation 6 ]