Hideo Takeda

Efficient asymmetric hydrogenation of α-aminoacetophenone derivatives leading to practical synthesis of (S)-(−)-levamisole☆

The neutral (2S,4S)-MCCPM-rhodium complex was found to be an efficient catalyst for asymmetric hydrogenation of α-aminoacetophenone derivatives. A practical asymmetric synthesis of (S)-(−)-levamisole was realized by using this hydrogenation as a key reaction.

Practical asymmetric synthesis of (R)-(-)-phenylephrine hydrochloride catalyzed by (2R, 4R)-MCCPM-rhodium complex

The neutral chiral N-substituted CPM-rhodium complexes were found to be efficient catalysts for asymmetric hydrogeantion of 3′-benzyloxy-2-(N-benzyl-N-methyl)aminoacetophenone hydrochloride. A practical asymmetric synthesis of (R)-(−)-phenylephrine hydrochloride catalyzed by newly synthesized (2R,4R)-MCCPM-rhodium complex has been achieved.

Efficient Preparation of Optically Active (S)-(-)-3-Methyl-γ-butyrolactone by Catalytic Asymmetric Hydrogenation Using Chiral N-Substituted Pyrrolidinebisphosphine Rhodium Complexes

(S)-(-)-2-Methyl succinamic acid, which is a good precursor of (S)-(-)-3-methyl-γ-butyrolactone, can be prepared by homogeneous asymmetric hydrogenation of 2-methylene succinamic acid catalyzed by (2S, 4S)-N-substituted-4-(diphenylphosphino)-2-[(diphenylphosphino)-methyl]pyrrolidine-rhodium complexes. Various N-substituted pyrrolidine-bisphosphines were synthesized to find the optimum ligand for this purpose and to compare the effects of the N-substituents.