p-Toluenesulfonic acid → 1-Bromo-3-(2-bromo-1,1-dimethoxyethyl)benzene

Participants

Reaction Conditions

Reaction Steps

A solution of 2-bromo-1-(3-bromophenyl)ethanone (48.23 g, 174 mmol) in MeOH (200 ml) was treated with trimethyl orthoformate (57.5 mL) and pTsOH (1.650 g, 8.68 mmol) and heated at reflux (75° C. oil bath) under nitrogen for 2.5 hrs. The mixture was cooled, concentrated to a viscous oil, diluted with Et2O (250 mL), and washed with 2.0 M aq. K2CO3 (100 mL), then brine. The organic layer was dried (MgSO4), filtered, and concentrated under reduced pressure, affording the product (56.43 g, 174 mmol, 100% yield) as a mobile yellow oil. 1H NMR (500 MHz, CDCl3) δ 7.69 (t, J=1.8 Hz, 1H), 7.48 (ddd, J=7.9, 2.0, 1.0 Hz, 1H), 7.43 (dq, J=7.8, 0.9 Hz, 1H), 7.29-7.24 (m, 2H), 3.60 (s, 2H), 3.24 (s, 6H). 13C NMR (126 MHz, CDCl3) δ 141.0, 131.5, 130.6, 129.6, 125.9, 122.3, 100.8, 49.5, 35.0. LCMS (M+H-MeOH)=291.97.

Provenance & Evidence