We describe herein the development of the first iridium-catalyzed allylic substitution using arylzinc nucleophiles. High enantioselectivities were obtained from the reactions, which used commercially available Grignard reagents as the starting materials. This methodology was also shown to be compatible with halogen/metal exchange reactions. Its synthetic potential is demonstrated by its application towards the formal synthesis of (+)-sertraline.

The copper-catalyzed asymmetric conjugate addition of dialkyl zinc leads to homochiral zinc enolates. These intermediates were trapped in situ with activated allylic electrophiles, without the need of additional palladium catalysis. High trans selectivity (85/15 to 100/0) and excellent enantioselectivities (up to 99%) could be attained. The functionalized nature of the electrophiles makes the new synthons potential candidates for further elaboration.

Thanks to iridium catalysis, arylzinc reagents undergo regioselective allylic substitution with very high enantioselectivity, when associated with phosphoramidite ligands.

Cyclohexane derivatives Q 0040 One-Pot Asymmetric Conjugate Addition-Trapping of Zinc Enolates by Activated Electrophiles. -Using the Cu catalyst shown in entry A), the corresponding products can be obtained with high diastereo-and enantioselectivity. -(RATHGEB, X.; MARCH, S.; ALEXAKIS*, A.; J. Org. Chem. 71 (2006) 15, 5737-5742; Dep. Org. Chem., Univ. Geneva, CH-1211 Geneva 4, Switz.; Eng.) -Jannicke 48-070

No abstract