4'-Chlorovalerophenone → tert-Butyl 4-(1-(4-chlorophenyl)-1-oxopentan-2-yl)benzoate

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A 3-neck flask was charged with NaOtBu (2.85 g, 28.6 mmol) and dry THF (50 mL) under nitrogen. Tris(dibenzylideneacetone)dipalladium(0) (0.26 g, 0.28 mmol) and (S)-Tol-Binap (0.47 g, 0.69 mmol) were then added under nitrogen. After stirring for 15 min, 1-(4-chlorophenyl)pentan-1-one (4.21 g, 21.0 mmol) was added, followed by tert-butyl 4-bromobenzoate (5.0 g, 19.1 mmol) under nitrogen. The mixture was heated at 60° C. for 8 hours. The mixture was diluted with heptane (100 mL) and poured into a solution of saturated NaHCO3 (aq) (60 mL) and ice (40 g). The resulting layers were separated, and the aqueous phase was back-extracted with methyl tert-butyl ether (50 mL). The combined organics were washed with saturated NaHCO3 (aq) then 10% NaCl(aq). The organic solution was filtered through a bed of silica 60 (84 g, wetted with 1:1 methyl tert-butyl ether/heptane), and washed with 1:1 methyl tert-butyl ether/heptane (600 mL). The combined filtrate was concentrated to afford an orange oil that was used directly for the next step: 1H NMR (500 MHz, CDCl3): δ 7.91 (d, J=8.1 Hz, 2H); 7.86 (d, J=8.4 Hz, 2H); 7.35 (d, J=8.4 Hz, 2H); 7.32 (d, J=8.2 Hz, 2H); 4.53 (t, J=7.2 Hz, 1H); 2.19-2.09 (m, 1H); 1.85-1.76 (m, 1H); 1.56 (s, 9H); 1.35-1.18 (m, 2H); 0.91 (t, J=7.3 Hz, 3H); LC1: 1.35 min. (M-tBu+H)+ 317.

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