A number of approaches to the synthesis of 2-alkyl-5,6-dihydrothiin-4-ones (1) are described. The treatment of 2-butylthian-4-one (3) with N-chlorosuccinimide gave a mixture of the alkenes (1a) and (4) and the corresponding reaction with the dioxolane (5) also proved to be non-regioselective. 2-Chlorodihydrothiin-4-one (6) was prepared and its reactions with a number of butylcopper reagents studied. The only product isolated from these reactions was 2,2-dibutylthian-4-one (12). 3-Chlorodihydrothiin-4-one (8) was successfully prepared and converted into 2-butyl-3-chlorothian-4-one (13) but dehydrohalogenation could not be achieved. A successful synthesis of the title compounds was achieved based on the generation and alkylation of the β-acylvinyl anion equivalent (14). Attempts to desulphurise 2-benzyl-5,6-dihydrothiin-4-one (1d) and related compounds in order to produce the α,β-unsaturated ketone (18) are discussed.