O,O'Diethyl acetals were prepared in high yields under mild conditions via the reaction of triethyl orthoformate with aldehydes and ketones in absolute ethanol in the presence of as low as 0.1 tool% of Yb(OTf)3. Using the same catalyst in THF-H2O, these O,O'-diethyl acetals could be converted to the corresponding carbonyl compounds efficiently. This new protection-deprotection protocol presents the advantages of ease of execution, high efficiency and good chemoselectivity.
A short and efficient synthesis of the selective human N-methyl-D-aspartate (NMDA) receptor 2A (NR2A) antagonist NVP-AAM077 is described. The target was achieved in 8 steps and in 54% overall yield from the commercially available chemical 3-methylbenzene-1,2-diamine. A NaIO4/DMF-based oxidation of the bromide to corresponding aldehyde and an addition of phosphinic acid ester to the aldimine successfully served as the key steps.