- (-)-Sparteine-mediated stereoselective directed ortho metalation of ferrocene diamides
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The utility of (-)-sparteine-mediated directed ortho metalation (DoM) has been investigated in stereoselective preparation of planar chiral ferrocenes derived from 1,1′-N,N,N′,N′- tetraisopropylferrocenedicarboxamide (5). In the synthesis of C 2-symmetric analogs of 5, the protocol (base, solvent, and two-step DoM) was found to be crucial for obtaining high enantio- and diastereo-selectivities of the products. A variety of highly enantioenriched mono and doubly functionalized derivatives of 5 have been synthesized. The synthetic applications of these compounds as chiral ligands in asymmetric alkylation of aldehydes and asymmetric palladium-catalyzed allylic substitutions have been demonstrated.
- Laufer, Radoslaw,Veith, Ulrich,Taylor, Nicholas J.,Snieckus, Victor
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p. 356 - 369
(2007/10/03)
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