LICLO4-INDUCED MANNICH REACTION - DIASTEREOSELECTIVE AND ENANTIOSELECTIVE SYNTHESIS OF BETA-AMINO KETONES BY ADDITION OF ENAMINES, IMINES OR SILYLENOLETHERS TO ALDEHYDES AND DIALKYLTRIMETHYLSILYLAMINES

LiClO4-mediated one-pot reactions of aldehydes with (trimethylsilyl)di alkylamines 2, 5 or 19 and C nucleophiles such as enamines 3, 10 and 1 2, imines 7 and 11 or (trimethylsilyl)enol ethers 8 and 9 afforded the corresponding aminoalkylation products in high yields. Whereas by usi ng aromatic aldehydes, such as benzaldehyde, pyridine-3-carbaldehyde o r thiophene-2-carbaldehyde, high diasteroselectivity was achieved, the aminoalkylation of aliphatic aldehydes such as isobutyraldehyde and p ivalaldehyde lacked diastereoselectivity. Enantioselective Mannich rea ctions using chiral enamines 22 and 23 are reported.