Salt-Free Enantioselective Iridium-Catalyzed Allylic Alkylations

Significance

Previous systems involving iridium-catalyzed allylic alkylations with β-carbonyl compounds require the use of the corresponding ­alkali-metal salt. The authors report iridium complexes of several phosphorus amidite ligands activated by the base TBD [1,5,7-triazabicyclo[4.4.0]dec-5-ene] which accommodate neutral β-carbonyl compounds. Further, the authors illustrate the utility of this method by providing a key intermediate in Stork’s quinine synthesis, the Ta­niguchi lactone, in high enantiomeric purity. Additionally, the catalytic system is applied to the intramolecular cyclization of 6 to yield cyclopropane 7 in high ee.