Benzaldehyde → (S)-3-benzyl-5-(1-methylpyrrolidin-2-yl)-pyridine

Participants

Reaction Steps

To a stirred solution of benzaldehyde (0.07 mL, 0.75 mmol) in freshly distilled THF was added dropwise 3-(1-methylpyrrolidin-2-yl)-1,4-bis-trimethylsilanyl-1,4-dihydropyridine i (0.21 g, 0.68 mmol). A degassed solution of TBAF in THF (1 M) stored over molecular sieves was slowly added to the mixture. The reaction mixture was stirred under Ar at RT for one day. It was then poured into a saturated aqueous solution of NaHCO3. The product was extracted with diethyl ether (2 times). The combined organic layers were washed with brine and dried over MgSO4. The solvent was evaporated under reduced pressure and the residue was purified by RPLC (silica gel, 10% MeOH/EtOAc) to give 31% (0.0525 g) of (S)-3-benzyl-5-(1-methylpyrrolidin-2-yl)-pyridine iv as a clear oil. IR (thin film, neat, NaCl): 3236, 2954, 2778, 1666, 1613, 1449, 1037 cm−1. 1H NMR (400 MHz, CDCl3) δ 8.40-8.34 (m, 2 H), 7.88 (dd, 1 H, J=1.6 and 13.2 Hz), 7.37-7.24 (m, 4 H), 5.84 (s, 1 H), 3.13-3.02 (m, 2 H), 2.25-1.69 (m, 10 H); 13C NMR (75 MHz, CDCl3) δ 148.43, 147.42, 143.90, 140.11, 138.19, 133.30, 133.25, 128.82, 127.95, 126.81, 74.24, 74.03, 69.15, 57.04, 40.47, 35.10, 22.51. HRMS Calcd for C17H20N2: 252.1626 [M+H]+. Found: 252.1635 [M+H]+. [α]25D−26 (CH2Cl2, c=1.51).

Provenance & Evidence