73323-65-6Relevant articles and documents
Catalytic Asymmetric Hydrogenation of Heteroarenes and Arenes
Kuwano, Ryoichi
, p. 715 - 719 (2016/01/15)
A trans-chelating chiral bisphosphine, PhTRAP, allows the ruthenium-catalyzed hydrogenation of various azoles to proceed with high enantioselectivity. The PhTRAP-ruthenium catalyst transformed indoles, pyrroles, imidazoles, and oxazoles into the correspon
Catalytic asymmetric hydrogenation of 2,3,5-trisubstituted pyrroles
Kuwano, Ryoichi,Kashiwabara, Manabu,Ohsumi, Masato,Kusano, Hiroki
, p. 808 - 809 (2008/09/20)
Catalytic asymmetric hydrogenation of N-Boc-protected pyrroles proceeded with high enantioselectivity by using a ruthenium catalyst modified with a trans-chelating chiral bisphosphine PhTRAP. The ruthenium catalyst prepared from Ru(η3-methallyl
Enzyme-catalyzed enantiomeric resolution of N-Boc-proline as the key-step in an expeditious route towards RAMP
Kurokawa, Masayuki,Shindo, Takeyuki,Suzuki, Masumi,Nakajima, Nobuyoshi,Ishihara, Kohji,Sugai, Takeshi
, p. 1323 - 1333 (2007/10/03)
For the preparation of both enantiomers of N-carbamoyl-2-methoxymethylpyrrolidine, the precursors of Enders' chiral auxiliaries, SAMP and RAMP, enzyme-catalyzed kinetic resolution of racemic N-carbamoyl, N-Boc, N-Cbz proline esters and prolinols were examined. B. licheniformis protease (subtilisin) preferentially hydrolyzed the (R)-carbamoylproline ester with an enantiomeric ratio (E) of 10. To a hydrophobic N-Cbz proline ester, subtilisin showed lower selectivity (E=2.8), and in contrast, a purified protease (isozyme A) from the earthworm showed the preference of (S)-enantiomer (E=13.6). In a practical sense, C. antarctica lipase B (Chirazyme L-2) was effective for the hydrolysis of both N-Boc and N-Cbz derivatives with E >100. The e.e. of (R)-N-carbamoyl-2-methoxymethylpyrrolidine was raised to be >99.9% by recrystallization at the N-Boc-prolinol stage, which was derived from the (R)-N-Boc-proline methyl ester (98.7% e.e.) through a preparative-scale enzyme-catalyzed resolution (49% yield) of the racemic substrate.