Journal article
Catalytic asymmetric synthesis of beta-sultams as precursors for taurine derivatives.
- 2009-07-18
Published in:
- Chemistry (Weinheim an der Bergstrasse, Germany). - 2009
English
Beta-sultams, biologically interesting sulfonyl analogues of beta-lactams, have been prepared by an organocatalytic asymmetric formal [2+2]-cycloaddition approach of non-nucleophilic imines with alkyl sulfonyl chlorides. In the case of very electron poor N-tosyl imines derived from chloral or ethylglyoxylate, this reaction type was catalyzed by cinchona alkaloids providing the heterocycles in high yield, with good diastereoselectivity and up to 94% ee. Mechanistic investigations suggested that the product formation proceeded via a zwitterionic imine-catalyst adduct. The scope was significantly extended by 2-pyridylsulfonyl imines derived from non-activated aromatic aldehydes employing Yb(OTf)3 as Lewis acid cocatalyst. The synthetic value of the strained enantioenriched beta-sultams was demonstrated by smooth nucleophilic ring opening reactions with O-, N- and C-nucleophiles yielding a variety of acyclic beta-aminosulfonyl (taurine) derivatives (sulfonates, sulfonamides, sulfones) without racemization or epimerization.
- Language
-
- English
- Open access status
- closed
- Identifiers
-
- DOI 10.1002/chem.200900496
- PMID 19609984
- Persistent URL
- https://sonar.ch/global/documents/111785
Statistics
Document views: 20
File downloads: