Reacción #52402

Ecuación de reacción

Intermediate 42

6-bromo-8-cyclopropyl-3,4-dihydro-4,4-dimethylspiro[2H-1-benzopyran-2,1′-cyclopropane]

tetrahydrofuran

tert-butyl lithium

pentane

dry ice

6-bromo-8-cyclopropyl-3,4-dihydro-4,4-dimethylspiro[2H-1-benzopyran-2,1′-cyclopropane]

carbon dioxide

→

title compound

[4-(8-Ethyl-2,2,4,4-tetramethyl-chroman-6-yl-ethynyl)phenyl] acetic acid

Disolventes

ethyl acetate

hexane

Condiciones de reacción

Procedimiento

Following general procedure R and using 6-bromo-8-cyclopropyl-3,4-dihydro-4,4-dimethylspiro[2H-1-benzopyran-2,1′-cyclopropane] (Intermediate 42, 0.45 g, 1.48 mmol), anhydrous tetrahydrofuran (5 mL), 1.7M solution of tert-butyl lithium solution in pentane ( 1.74 mL, 2.96 mmol) and carbon dioxide generated from dry ice, followed by flash column chromatography over silica gel (230-400 mesh) using 50% ethyl acetate in hexane as the eluent, the title compound was obtained as a white solid (0.34 g, 85%).

Fuente