ISSN:
1434-193X
Keywords:
Asymmetric synthesis
;
Chiral allylic anions
;
(-)-Sparteine
;
Enantioselective deprotonation
;
Stereochemistry of electrophilic allylic substitution
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The title reaction leads to diastereomeric lithium carbanion pairs that are configurationally unstable and equilibrate even at temperatures below -50 °C. The initially formed epimer (1S)-epi-10 is rapidly converted to the thermodynamically more stable (1R)-10 (in toluene solution). Carboxylation, acylation with acid chlorides, stannylation, and silylation take place at the α-position with stereoinversion (79-86% ee). Methylating agents attack the γ-position; here, the stereochemical course depends on the leaving group, anti-SE′ for the iodide (50% ee) and syn-SE′ (48% ee) for the tosylate.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
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