C[Si](C)(C)N[Si](C)(C)C.C1(P(C2CCCCC2)C2C=CC=CC=2C2C=CC=CC=2N(C)C)CCCCC1.[C:38]([O:42][C:43](=[O:45])[CH3:44])([CH3:41])([CH3:40])[CH3:39].[Cl:46][C:47]1[CH:52]=[C:51](Cl)[C:50]([CH3:54])=[CH:49][N:48]=1>C1(C)C=CC=CC=1.C(=CC(C=CC1C=CC=CC=1)=O)C1C=CC=CC=1.[Pd]>[C:38]([O:42][C:43](=[O:45])[CH2:44][C:51]1[C:50]([CH3:54])=[CH:49][N:48]=[C:47]([Cl:46])[CH:52]=1)([CH3:41])([CH3:40])[CH3:39]Hexamethyl disilazane (1.33 g, 8.23 mmol) is dissolved in dry toluene (15 ml) under an atmosphere of argon. After thoroughly purging the solvent with argon, the solution is cooled to −78° C., and n-BuLi (5.1 ml of a 1.6 M solution in hexanes, 8.23 mmol) is added. The mixture is stirred for 15 minutes at −78° C. and for 15 minutes at rt, whereupon a clear solution is obtained. Palladium dibenzylideneacetone (Pd2(dba)3, 151 mg, 0.16 mmol) and (2′-dicyclohexylphosphanyl-biphenyl-2-yl)-dimethyl-amine (136 mg, 0.35 mmol) are added. The mixture is stirred for 10 minutes at RT, then it is cooled to −10° C. Acetic acid tert-butyl ester (924 mg, 7.96 mmol) is slowly added heat. After 10 minutes at −10° C., 2,4-dichloro-5-methyl-pyridine (889 mg, 5.49 mmol) is added in one portion. The reaction mixture is allowed to warm to RT. After 1 h, TLC analysis indicated complete consumption of starting materials. The reaction mixture is diluted with EtOAc and poured into a saturated aqueous NH4Cl solution. The organic layer is separated, washed with brine, dried over Na2SO4, and the solvent is evaporated. The residue is purified by FCC (hexanes/EtOAc, gradient from 100:0 to 90:10) to afford the title compound. 1H NMR (CDCl3, 400 MHz): δ 1.45 (s, 9H), 2.26 (s, 3H), 3.52 (s, 2H), 7.18 (s, 1H), 8.18 (s, 1H). ES+−MS: 242.2, 244.2 (Cl) [M+H]+.
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