Josiphos ligand catalyzed 1,4-addition

Asymmetric copper-catalyzed 1,2-additions of a variety of alkyl Grignard reagents to enones has also been recently described, providing entry to nonracemic tertiary allylic alcohols. a,P-Disubstituted cases work well, run in f-BuOMe at low temperatures (-78 °C or -60 °C over 5-10 hours. The best source of chirality was found to be the JOSIPHOS ligand (ent-136), while CuBr DMS (5 mol%) was the favored source of copper(I) interestingly, Cu(OAc)2 led to racemic products. Yields... 

Palladium-catalyzed asymmetric addition of hydrogen phosphonates to norbor-nenes proceeded efficiently when sterically hindered Josiphos ligands were used, to produce the corresponding phosphonates (210) in high enantioselectivity (Scheme 79). 

Ferrocene-derived ligand (l ,S)-Josiphos, which is widely used for catalytic asymmetric hydrogenation reactions, is also a good catalyst for the asymmetric copper-catalyzed 1,4-addition. Reaction in f-BuOMe in the presence of 6 mol% of this ligand gives products with up to 98%. ... 

High ees were achieved recently with Cu-JOSIPHOS complexes for the Michael addition of Grignard reagents to various substrates (302). Another ferrocene-based ligand, TANIAPHOS, was also efficient in the copper-catalyzed reductive addition of aldehydes and ketones to methyl acrylate (303). 

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