Nickel-catalysed asymmetric SN2′ substitution chemistry of Baylis–Hillman derived allylic electrophiles

Trends in the Usage of Bidentate Phosphines as Ligands in Nickel Catalysis

“…Woodward and co-workers tested ( R )-1-(( S p )-2-(diphenylphosphino)­ferrocenyl)­ethyldicyclohexylphosphine (SL-J001-1) and Ni­(acac) 2 (2:1) in an asymmetric substitution of allylic electrophiles with AlMe 3 and observed a low conversion, yield, and ee with slight selectivity for the R isomer. ( R )-BINAP gives the same result.…”

Enantioselective and Enantiospecific Transition-Metal-Catalyzed Cross-Coupling Reactions of Organometallic Reagents To Construct C–C Bonds

“… 279 A Ni-catalyzed allylic substitution was also developed by Woodward and co-workers, in which Baylis–Hillman adduct 345 could be coupled with AlMe 3 ( Scheme 37 b). 280 , 281 Axially chiral Ferrocite L92 imparted high enantioinduction, but good control of regioselectivity remains an unsolved obstacle.…”

Mapping the Mechanism of Nickel‐Ferrophite Catalysed Methylation of Baylis–Hillman‐Derived SN2′ Electrophiles

“…We found pure 4 was attained by AlMe 3 methylation of 1 in the presence of un‐ligated Ni(acac) 2 . The enantiomers of 3 were initially assigned1 by assuming the second eluting species under GC octakis(2,6‐di‐ O ‐methyl‐3‐ O ‐pentyl)‐γ‐cyclodextrin analysis corresponded to the ( R ) enantiomer as it had in the analogous ethyl addition product (–)‐( R )‐ 5 (Scheme ) 4. The assignment of the ethyl derivative is secured on the basis of ester hydrolysis and an X‐ray structure of the insoluble ( R )‐PhCHMeNH 2 amine salt ( R , R )‐ 6 4.…”

“…We briefly reported an enantioselective (49–94 % ee ) methylation of 1 – 2 1 in the presence of the ( R p ) planar chiral ferrophite ligands L A ‐L B (Scheme ) 2. The allylic chloride 1 and acetate 2 were chosen as these substrates are readily available through Baylis–Hillman chemistry and lead to useful α‐chiral methylene carboxylate products 3.…”