L-Proline-catalysed direct asymmetric aldol reaction of acetone with various aldehydes in PEG-400 is described. Recycling of the catalyst and solvent (PEG) was possible up to ten runs without loss of catalyst activity. l-Proline was also found to be an efficient catalyst for the asymmetric transfer aldol reaction between various aldehydes and diacetone alcohol for the first time. Good yields and enantioselectivities were observed with both methods.
Bibliographical noteFunding Information:
Three of us (N.R.R., S.S.S. and C.N.) thank CSIR New Delhi for financial support. IICT Communication no. 050704
- Aldol reaction
- Transfer aldol reaction