Synthesis of 2,3-Dihydro-6-methylthieno(2,3-c)furan (Kahweofuran) a Coffee Aroma Component, from an Acyclic Precursor

Kahweofuran 1, one of the impact flavours of roasted coffee, was obtained from the acyclic unsaturated ester 8, produced in a Stobbe condensation of alpha-methylcinnamaldehyde with dimethyl succinate, through the key intermediate tetrahydrothiophene 14 and the C-7 derivatives 20 or 24, respectively.