Propanoic acid, 2-bromo-2-methyl-, ethyl ester → 2-Methyl-2-(tetrahydro-pyran-4-ylsulfanyl)-propionic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

A solution of 153 g (0.96 mol) of thioacetic acid S-(tetrahydro-pyran-4-yl) ester in EtOH (3.5 L) is degassed with nitrogen over 0.5 h and 125 g (2.23 mol) of KOH are added. Then a solution of 250 mL (1.68 mol) of ethyl α-bromoisobutyrate in EtOH (1 L) are added over 0.5 h, during which the temperature increased to 40° C. The reaction is stirred for 18 h at RT under a nitrogen atmosphere. The reaction mixture is filtered, the solid is washed with EtOH (0.5 L) and the filtrate is concentrated under reduced pressure. The crude material is dryloaded onto silica and purified by dry-flash column chromatography (silica, eluent: nheptanes, 2-10% EE) to afford 158 g of 2-methyl-2-(tetrahydro-pyran-4-ylsulfanyl)-propionic acid ethyl ester. Yield: 71%; ESI-MS: 233 [M+H]+

Provenance & Evidence