Synthesis of 2-mercaptobenzaldehyde, 2-mercaptocyclohex-1- enecarboxaldehydes and 3-mercaptoacrylaldehydes

Article abstract of DOI:10.1002/cjoc.201200433

A novel one-pot approach for the preparation of 2-mercaptobenzaldehyde, 2-mercaptocyclohex-1-enecarboxaldehydes and 3-mercaptoacrylaldehydes [(Z)-3-mercapto-2-methyl-3-phenylacrylaldehyde, 3-mercapto-3-(o-tolyl) acrylaldehyde)] starting from ortho-bromobenzaldehyde, 2-chlorocyclohex-1- enecarbaldehydes, (Z)-3-chloro-2-methyl-3-phenylacrylaldehyde and 3-chloro-3-(o-tolyl)acrylaldehyde is reported. The reaction of sulfur with the Grignard reagent of the acetal for the protection of the aldehyde group affords the title compounds through hydrolysis with dilute hydrochloric acid in high yields. One-pot synthesis of 2-mercaptobenzaldehyde, 2-mercaptocyclohex-1- enecarboxaldehydes and 3-mercaptoacrylaldehydes was developed by the reaction of the Grignard reagent with sulfur. The novel procedure showed high yields of the desired products, easy work-up, short reaction time, no catalyst, no hazardous phosphine ligands, no strong and foul smell sulfur-containing reagents, no environmental problem and mild reaction conditions in comparison with other methods, which are the strong points of the present procedure. Copyright