2-Bromopyridine → 2-Chloro-7-(3-chloro-4-methoxy-phenyl)-5-cyclopentyl-5-hydroxy-3-oxo-heptanoic acid methyl ester

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Methyl-2-chloroacetoacetate (2.5 g, 16.9 mmol) was added to a cooled 0° C. suspension of NaH (0.68 g, 16.9 mmol, 60% dispersion in mineral oil) in THF (30 ml). After 15 min the solution was cooled to −40° C. and n-BuLi (10.6 mL, 16.9 mmol, 1.6M in hexanes) was added. The resulting dianion was stirred for an additional 30 min and then treated with a solution of 3-(3-Chloro-4-methoxy-phenyl)-1-cyclopentyl-propan-1-one (1.5 g, 5.6 mmol, compound was prepared analogously to Step 1 of Example A(82), where 4-bromo-2-chloro-1-methoxybenzene was substituted in place of 2-Bromopyridine) in THF (10 ml). After stirring for 1 h at −40° C., the reaction mixture was quenched with saturated NH4Cl and extracted with EtOAc. The organic layers were washed with brine, dried with Na2SO4 and concentrated to an orange oil that was used without further purification.

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