Synthesis
General procedure for the synthesis of 2-(4-bromophenyl)-pyrrolidine from 5-(4-bromophenyl)-3,4-dihydro-2H-pyrrole: NaBH4 (1.52 g, 40 mmol) was added to 5-(4-bromophenyl)-3,4-dihydro-2H-pyrrole (4.48 g, 20 mmol) dissolved in a H2O/MeOH (30 mL, v /v 1:4) solution. The reaction mixture was stirred for 4 hours and then slowly warmed up to room temperature. After the completion of the reaction was monitored by TLC, 2N HCl was added to quench the unreacted NaBH4. Subsequently, the organic and aqueous layers were separated by diluting the reaction mixture with deionized water and ether. The aqueous layer was further extracted with ether and the combined organic phases were adjusted to pH 12-13 with 4 M NaOH and washed with ethyl acetate. All organic extracts were combined, washed with saturated brine and dried over anhydrous Na2SO4. The solvent was removed by concentration under reduced pressure to give the crude product 2-(4-bromophenyl)-pyrrolidine as a yellow oil (3.8 g, 84% yield), which could be used in the subsequent reaction without further purification.LC-MS (ESI) m/z: 226 (M + 1)+.
References
[1] Patent: US2010/35883, 2010, A1. Location in patent: Page/Page column 99
[2] Patent: WO2011/130661, 2011, A1. Location in patent: Page/Page column 196
[3] Journal of Organic Chemistry, 2005, vol. 70, # 9, p. 3705 - 3708
[4] Patent: WO2008/70447, 2008, A2. Location in patent: Page/Page column 49
[5] Patent: WO2009/112565, 2009, A1. Location in patent: Page/Page column 42
