I[C:2]1[C:3]2[S:10][CH:9]=[CH:8][C:4]=2[N:5]([CH3:7])[N:6]=1.C([Mg]Cl)(C)C.[CH2:16]([Sn:20]([CH2:26][CH2:27][CH2:28][CH3:29])([CH2:22][CH2:23][CH2:24][CH3:25])Cl)[CH2:17][CH2:18][CH3:19]>C1COCC1>[CH3:7][N:5]1[C:4]2[CH:8]=[CH:9][S:10][C:3]=2[C:2]([Sn:20]([CH2:22][CH2:23][CH2:24][CH3:25])([CH2:26][CH2:27][CH2:28][CH3:29])[CH2:16][CH2:17][CH2:18][CH3:19])=[N:6]1To a solution of 3-iodo-1-methyl-1H-thieno[3,2-c]pyrazole (290 mg, 1.10 mmol) in THF (6 mL) at −15° C. was slowly added isopropylmagnesium chloride (2.0 M in THF, 0.66 mL, 1.32 mmol). The bright yellow heterogeneous reaction mixture was stirred at −15° C. for 20 min then tributylchlorostannane (0.36 mL, 1.32 mmol) was added dropwise. Stirring was continued at −15° C. for 20 min then at room temperature for 2 h. The reaction mixture was quenched with water and extracted with EtOAc (2×). The combined organics were washed with brine then dried over MgSO4 and concentrated. The residue was purified by silica gel chromatography with 10% to 20% EtOAc/heptane (0.5% Et3N) gave 298 mg (63%) of 1-methyl-3-tributylstannanyl-1H-thieno[3,2-c]pyrazole as a pale yellow oil. 1H NMR (CDCl3, 300 MHz): δ (ppm) 7.36 (d, J=5.3 Hz, 1H), 6.90 (d, J=5.3 Hz, 1H), 4.06 (s, 3H), 1.54-1.67 (m, 6H), 1.36 (dq, J=14.7, 7.3 Hz, 6H), 1.13-1.22 (m, 6H), 0.90 (t, J=7.3 Hz, 9H).
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