2-Dicyclohexylphosphino-2',6'-dimethoxybiphenyl → 6-chloro-3-cyclobutyl-1-trityl-1H-pyrazolo[4,3-c]pyridine

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Reaction Conditions

Reaction Steps

Reference: PCT Int. Appl., 2010056631, 2010. To a solution of zinc chloride (1.5 ml, 3.591 mmol, 1.9M in 2-methyl THF) at 0° C. was added a solution of cyclobutyl magnesium chloride in (9.20 ml, 4.60 mmol, 0.5 M in 2-methyl-THF). The reaction solution was stirred at 0° C. to r.t for 1 hr, and then transferred into a mixture of 6-chloro-3-iodo-1-trityl-1H-pyrazolo[4,3-c]pyridine (3a, 1 g, 1.917 mmol), Pd(OAc)2 (0.043 g, 0.192 mmol) and S-Phos (2-dicyclohexylphosphino-2′,6′-dimethoxybiphenyl, 0.118 g, 0.287 mmol) at r.t. The result dark suspension was stirred at r.t for 3 hr and then was quenched with water and extracted with ethyl acetate. The organic layer was concentrated and purified by column chromatography on silica gel (50 g, eluting with 20% ethyl acetate/hexanes) to give 6-chloro-3-cyclobutyl-1-trityl-1H-pyrazolo[4,3-c]pyridine (483 mg, 56%) as a light yellow solid. MS ESI calc'd. for C29H24Cl1N3[M+1]+ 450, found 450.

Provenance & Evidence