L-Threonine has been found to be an efficient catalyst for the asymmetric alpha-hydroxymethylation of cyclohexanone with formalin. Reducing the amount of water in the reaction by the addition of magnesium sulfate as a dehydrating additive significantly improves the yield. Applications of (S)-2-hydroxymethyl cyclohexanone and the chiral building blocks derived therefrom for the synthesis of pharmaceutical compounds and natural products have been explored. (C) 2009 Elsevier Ltd. All rights reserved.
Direct asymmetric α-hydroxymethylation of ketones in homogeneous aqueous solvents
A chiral prolinamide-based zinc complex promotes the aldol reaction of ketones with aqueous formaldehyde, giving the corresponding adducts in good yields and high ees. The efficient direct aldol reaction of formaldehyde with ketones in homogeneous aqueous solution is presented for the first time. (C) 2010 Elsevier Ltd. All rights reserved.