Chitosan Aerogel Beads as a Heterogeneous Organocatalyst for the Asymmetric Aldol Reaction in the Presence of Water: An Assessment of the Effect of Additives
The catalytic properties of chitosan aerogel for the direct asymmetric aldol reaction in water assisted by various surfactants and acid co-catalysts have been evaluated by employing a range of donor and acceptor systems. A beneficial effect on both the yields and nantioselectivities was observed, and the combination of surfactants and acid co-catalysts has proven particularly useful in the case of
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.