Water → 6'-bromo-4-methoxyspiro[cyclohexane-1,2'-inden]-1'(3'H)-one

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

A mixture of isomers of 6′-bromo-4-hydroxyspiro[cyclohexane-1,2′-inden]-1′(3′H)-one (Intermediate 5 Step 2, 12.7 g, 43.0 mmol) was dissolved in THF (210 mL) under N2 and cooled to 0° C. Potassium tert-butoxide (5.79 g, 51.6 mmol) was added portionwise and the mixture was stirred at 0° C. for 25 min. Methyl iodide (4.30 mL, 68.8 mmol) was added. The cooling bath was removed, and the mixture was stirred at r.t. Additional potassium tert-butoxide (0.483 g, 4.30 mmol) was added twice, after 2 h and 3 h respectively, and then the mixture was stirred for 2 h. Water (100 mL) was added and the resulting solution was partitioned between aq. NaCl solution (200 mL), and EtOAc (200 mL). The aq. phase was extracted with another portion of EtOAc (100 mL). The combined organic phases were dried (MgSO4) and evaporated to give 12.5 g (94% yield) of a mixture (approx. 80:20) of:

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