Diethylaminosulphur trifluoride (DAST) as an effective reagent for preparation of methyl 2-arylpropanoates from 1-aryl-1,1-dimethoxypropan-2-ols

Abstract

Treatment of dimethylacetals of aryl 1-hydroxyethyl ketones [ArC(OMe)₂CH(OH)Me](Ar = Ph, 4-PhC₆H₄, 4-BuⁱC₆H₄, 4-MeOC₆H₄, 4-BrC₆H₄, 6-MeOnaphthalen-2-yl) with diethylaminosulphur trifluoride (DAST) affords smoothly the methyl 2-arylpropanoates in good yield via aryl-group migration. On the other hand, treatment of aryl 1-hydroxyethyl ketones with DAST gives the corresponding aryl 1-fluoroethyl ketones [ArCOCHFMe](Ar = Ph, 4-PhC₆H₄, 4-BuⁱC₆H₄) in high yield.