Triphenylphosphine → (+/-)-5-[1-(4'-Tert-butyl-2,6-dimethyl-biphenyl-4-yloxy)-ethyl]-thiophene-2-carboxylic acid ethyl ester

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Reaction Steps

A mixture of (±)-5-(1-hydroxy-ethyl)-thiophene-2-carboxylic acid ethyl ester (0.416 g, 2.08 mmol), 4′-tert-butyl-2,6-dimethyl-biphenyl-4-ol (0.561 g, 2.20 mmol), and PPh3 (0.787 g, 3.00 mmol) is dissolved in toluene (19 mL) and treated with 1,1′-(azodicarbonyl)dipiperidine (ADDP, 0.760 g, 3.01 mmol) and stirred overnight at rt. The mixture is diluted with MeOH until homogeneous and conc. The residue is loaded onto silica gel and eluted using hexanes with an ethyl acetate gradient from 0% to 40% giving (±)-5-[1-(4′-tert-butyl-2,6-dimethyl-biphenyl-4-yloxy)-ethyl]-thiophene-2-carboxylic acid ethyl ester (0.604 g, 671%) as a clear syrup.

Provenance & Evidence