An improved and safer synthesis of (R)- and (S)-4,4'-diaminomethyl-BINAP.

Wissam Dayoub (1) , Alain Favre-Reguillon (2, 1) , Mikael Berthod (1) , Erwann Jeanneau (3) , Gérard Mignani (4) , Marc Lemaire (1)

1 ICBMS - Institut de Chimie et Biochimie Moléculaires et Supramoléculaires
2 LGPC - Laboratoire de Génie des Procédés Catalytiques
3 UCBL - Université Claude Bernard Lyon 1
4 Rhodia Centre de Recherche

(R)- and (S)-4,4′-diaminomethyl-BINAP were prepared in three steps from enantiomerically pure BINAPO in a global yield of 52 %. A regioselective bromination of BINAPO with NBS in HMimPF6 gave the desired 4,4′-dibromo-BINAPO in quantitative yield, and the recyclability of the ionic liquid was demonstrated. Copper cyanide cyanation of 4,4′-dibromo-BINAPO gave the 4,4′-dicyano-BINAPO in 70 % yield. Both enantiomers were characterized by NMR spectroscopy and HPLC analysis, and the structures were confirmed by X-ray crystallography. The cyano and phosphane oxide groups of the resulting 4,4′-dicyano-BINAPO were reduced in one step to the corresponding 4,4′-diaminomethyl-BINAP by using tetramethyldisiloxane/Ti(OiPr)4 in 75 % yield.

Mots clés: Ligand design; Ionic liquids; Reduction; Silicon; Synthetic methods

Domaines: Chimie organique

Wissam Dayoub, Alain Favre-Reguillon, Mikael Berthod, Erwann Jeanneau, Gérard Mignani, et al.. An improved and safer synthesis of (R)- and (S)-4,4'-diaminomethyl-BINAP.. European Journal of Organic Chemistry, 2012, 2012 (16), pp.3074-3078. ⟨10.1002/ejoc.201200219⟩. ⟨hal-01170157⟩