Li-Ren Jin

(1S,3S,4S)-tert-Butyl N-[1-benzyl-3-hydr­oxy-5-phenyl-4-(picolinamido)pent­yl]carbamate

The title compound, C29H35N3O4, was obtained by the reaction of (2S,4S,5S)-tert-butyl N-(4-amino-1-benzyl-3-hydroxy-5-phenylpentyl)carbamate and picolinic acid using oxalyl chloride as a chlorinating reagent to activate the carboxyl group. In the crystal structure there are two molecules in the asymmetric unit, which are aligned edge-to-face. In one molecule, the pyridyl ring forms a dihedral angle of 22.0 (1)° with the phenyl ring of the terminal benzyl group and 14.3 (1)° with the other phenyl ring; in the other molecule, the corresponding angles are 12.1 (1) and 10.6 (1)°, respectively. The packing is stabilized by intermolecular hydrogen bonds and C—H⋯π interactions.

(S)-1,5-Dibenzyl-3-tert-butyl­imidazol­idin-4-one

The title compound, C21H26N2O, was obtained as an unexpected by-product when attempting to prepare (S)-2-benzyl-N-tert-butyl-1,2,3,4-tetrahydroisoquinoline-3-carboxamide from (S)-2-benzylamino-N-tert-butyl-3-phenylpropanamide and dimethoxymethane. The molecules are linked by weak C—H⋯O hydrogen bonds, generating linear chains parallel to the b axis. C—H⋯π interactions provide further stability for the crystal structure. The planes of the two phenyl rings make a dihedral angle of 84.1 (1)°. The absolute configuration was known from the starting material.

(3S, 4S)-tert-butyl 4-amino-3-hydroxy-5-phenyl-pentanoate

The title compound, (I), which belongs to the class of -amino alcohols, is a key intermediate used to synthesize chiral ligands, such as bis(oxazoline) ligands, for asymmetric catalysts. The majority of the syntheses of these ligands have followed a general synthetic route in which oxalic acid or substituted malonic acids were first condensed with the corresponding optically active -amino alcohols to form the bis(hydroxy)amide derivatives. The hydoxy groups in the bis(hydroxy)amide were then activated and the resulting intermediate was cyclized to provide the bis(oxazoline) ligands (Ghosh et al., 1998).