Synthesis and Crystal Structure of the Chiral β-amino Alcohol (S)-α,α-diphenyl-2-pyrrolidine Methanol

Abstract

Optically pure (S)-α,α-diphenyl-2-pyrrolidine methanol was prepared from L-proline via protection of the amino group, reaction with the Grignard reagents and deprotection of the amino-protected groups in 54.4% yield. The synthetic conditions to prepare (S)-α,α-diphenyl-2-pyrrolidinemethanol were optimised. Single crystal X-ray diffraction analysis revealed that the molecular structure of the compound was enantiomerically pure. The crystals are orthorhombic, space group P2( 1) 2( 1) 2( 1), with unit cell parameters a = 8.9000(18) Å, b = 9.2405(18) Å, c = 16.671(3) Å, V = 1371.1(5) Å3, Dx = 1.227 g cm−3, Z =4, T = 113(2)K, F(000) = 628, R1 = 0.0335 and wR2 = 0.0707. The absolute structure parameter was – 1.6(17).