Journal
CHIRALITY
Volume 29, Issue 6, Pages 257-272Publisher
WILEY
DOI: 10.1002/chir.22678
Keywords
asymmetric Michael reactions; cyclopropanation; enantioselectivity; phase transfer catalysis; sugar-based crown ethers
Funding
- New Szechenyi Development Plan [TAMOP-4.2.1/B-09/1/KMR-2010-0002]
- Orszagos Tudomanyos Kutatasi Alapprogramok [PD 112166]
Ask authors/readers for more resources
A few new l-threitol-based lariat ethers incorporating a monoaza-15-crown-5 unit were synthesized starting from diethyl l-tartrate. These macrocycles were used as phase transfer catalysts in asymmetric Michael addition reactions under mild conditions to afford the adducts in a few cases in good to excellent enantioselectivities. The addition of 2-nitropropane to trans-chalcone, and the reaction of diethyl acetamidomalonate with -nitrostyrene resulted in the chiral Michael adducts in good enantioselectivities (90% and 95%, respectively). The substituents of chalcone had a significant impact on the yield and enantioselectivity in the reaction of diethyl acetoxymalonate. The highest enantiomeric excess (ee) values (99% ee) were measured in the case of 4-chloro- and 4-methoxychalcone. The phase transfer catalyzed cyclopropanation reaction of chalcone and benzylidene-malononitriles using diethyl bromomalonate as the nucleophile (MIRC reaction) was also developed. The corresponding chiral cyclopropane diesters were obtained in moderate to good (up to 99%) enantioselectivities in the presence of the threitol-based crown ethers.
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