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Sparteines as a Chiral Ligand for Asymmetric Synthesis

The alkaloid (-)-sparteine (S0461) has found widespread use as a chiral ligand for asymmetric reactions.1) The complex formed from S0461 and organolithium has recognized enantiotopic sides in its carbanions and prochiral reaction partner’s protons.2,3) Asymmetric aldol additions using S0461 and TiCl4 have provided aldol products with excellent chiral selectivities.4) Palladium-catalyzed oxidation and following resolutions of secondary alcohols assisted by S0461 as a ligand have provided the optically activated alcohols.5,6)(+)-Sparteine (S0884) is not easily obtained from natural source compared with S0461. However, S0884 has potential for a chiral ligand which affords the products having an opposite configuration to those obtained by using S0461.3)

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