Highly Anti-Selective One-Pot Multicomponent Synthesis of Mannich-Type N-Acylated β-Amino Acid Derivatives by Copper or Sodium Salt Catalysis
摘要:
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 alpha-substituted enolate anion. This steric interaction helps the addition to take place through the less-hindered face to produce the anti-isomers predominantly.Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications (R) to view the free supplemental file.
An efficient triphenylphosphine-catalyzed synthesis of beta-acetamido carbonyls via multicomponent reaction of aromatic aldehydes, enolizable ketones or beta-keto esters, acid chlorides and acetonitrile at room temperature is described. The process is remarkably simple, environmentally benign, and uses Lewis base for the first time in such type of reaction.