Journal
JOURNAL OF ORGANIC CHEMISTRY
Volume 76, Issue 9, Pages 3005-3015Publisher
AMER CHEMICAL SOC
DOI: 10.1021/jo200431v
Keywords
-
Categories
Funding
- DFG [SPP 1179]
- Cusanuswerk
- Studienstiftung des deutschen Volkes
Ask authors/readers for more resources
The proline-catalyzed self-condensation of aliphatic aldehydes in DMSO with varying amounts of catalyst was studied by in situ NMR spectroscopy. The reaction profiles and intermediates observed as well as deuteration studies reveal that the proline-catalyzed aldol addition and condensation are competing, but not consecutive, reaction pathways. In addition, the rate-determining step of the condensation is suggested to be the C-C bond formation. Our findings indicate the involvement of two catalyst molecules in the C-C bond formation of the aldol condensation, presumably by the activation of both the aldol acceptor and donor in a Mannich-type pathway. This mechanism is shown to be operative also in the oligomerization of acetaldehyde with high proline amounts, for which the first in situ detection of a proline-derived dienamine was accomplished. In addition, the diastereoselectivity of the aldol addition is evidenced to be time-dependent since it is undermined by the retro-aldolization and the competing irreversible aldol condensation; here NMR reaction profiles can be used as a tool for reaction optimization.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available