Synthesis of enantiomerically enriched allenes by (-)-sparteine-mediated lithiation of alkynyl carbamates

Authors
Schultz-Fademrecht, C Wibbeling, B Frohlich, R Hoppe, D
Citation
C. Schultz-fademrecht et al., Synthesis of enantiomerically enriched allenes by (-)-sparteine-mediated lithiation of alkynyl carbamates, ORG LETT, 3(8), 2001, pp. 1221-1224
Citations number
52
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
ORGANIC LETTERS
ISSN journal
15237060 → ACNP
Volume
3
Issue
8
Year of publication
2001
Pages
1221 - 1224
Database
ISI
SICI code
1523-7060(20010419)3:8<1221:SOEEAB>2.0.ZU;2-2
Abstract
The alpha -deprotonation of alkynyl carbamates 3 with the chiral base (-)-s parteine (4)/n-butyllithium, transmetalation with CITi((OPr)-Pr-/)B-3 and s ubsequent substitution with an aldehyde results in the formation of enantio enriched 4-hydroxyallenyl carbamates 11. Stereoselection is determined by d ynamic resolution of the lithium/(-)-sparteine complexes by selective cryst allization.