Yield:-

Steps:

Multi-step reaction with 2 steps
1.1: Br₂; aq. Na₂CO₃ / CH₂Cl₂ / 0.5 h / 0 °C
2.1: Mg; 1,2-dibromoethane / tetrahydrofuran / 0.5 h
2.2: 77 percent / tetrahydrofuran / 20 °C

References:

Chen, Chen;Wilcoxen, Keith M.;Huang, Charles Q.;Xie, Yun-Feng;McCarthy, James R.;Webb, Thomas R.;Zhu, Yun-Fei;Saunders, John;Liu, Xin-Jun;Chen, Ta-Kung;Bozigian, Haig;Grigoriadis, Dimitri E. [Journal of Medicinal Chemistry,2004,vol. 47,# 19,p. 4787 - 4798]