An economical, simple, and efficient direct aldol reaction via the double activation of both aldehydes and ketones by ammonia has been developed. An unprecedented tandem Mannich reaction was observed when hydroxybenzaldehydes, pyrrole-2-carboxyaldehyde, and indole-3-carboxyaldehyde were employed to afford 2,2-dimethyl-6-aryl-4-pyrilidinones in moderate to good yields.
Tandem Catalysis by Lipase in a Vinyl Acetate-Mediated Cross-Aldol Reaction
作者:Manjeet Kumar、Bhahwal A. Shah、Subhash C. Taneja
DOI:10.1002/adsc.201000980
日期:2011.5
The lipase Novozym435 (0.6% w/w) was used in tandem with organocatalysts in a first vinyl/isopropenyl acetate‐mediated aldol reaction. The reaction was facilitated through the lipase‐catalyzed in situ generation of acetaldehyde/acetone. The important features of the present methodology include the mild and facile reaction conditions, regenerability of the lipase, comparatively high yields and minimal
Electron deficiency of aldehydes controls the pyrrolidine catalyzed direct cross-aldol reaction of aromatic/heterocyclic aldehydes and ketones in water
作者:Swapandeep Singh Chimni、Dinesh Mahajan
DOI:10.1016/j.tet.2005.03.045
日期:2005.5
A synthetically useful pyrrolidine catalyzed direct cross-aldol reaction of aromatic/heterocyclic aldehydes with ketones in water affords the aldol addition product in up to 93% yield. Electrophilicity of the aldehydes controls the course of the reaction.
A novel DNA-catalyzed aldol reaction in water has been developed. This approach will be helpful in learning the role of DNA as a catalyst in the early stage during the development of life on earth.
Chitosan hydrogel: A green and recyclable biopolymer catalyst for aldol and Knoevenagel reactions
作者:K. Rajender Reddy、K. Rajgopal、C. Uma Maheswari、M. Lakshmi Kantam
DOI:10.1039/b610355c
日期:——
Chitosan hydrogel is efficiently utilized as an organocatalyst for aldol and Knoevenagel reactions, providing the products in high yields with a high chemoselectivity under biphasic conditions. The catalyst was recovered by simple filtration and reused several times without significant loss of activity.