BEDT-TTF and related donor molecules - Made easy

Two new general approaches to TTF-based donor molecules have been developed. Route A gave, after basic cleavage of thiapendione (1) and direct alkylation of intermediate (2), the corresponding 4,5-disubstituted 1,3-dithiol-2-ones of general formula 4 as exemplified in Schemes 1 and 2. The more versatile route B involves isolation of the unstable intermediate 2 as chelate complex 3, which then gives upon treatment with alkyl/acyl halides compounds of type 4. Compounds (4) can either be coupled/cross-coupled in triethyl phosphite in known manner to give symmetric/asymmetric donors molecules or be used as precursors for the preparation of other sulfur containing heterocycles or metal complexes. Versatility, yields and high purity of intermediates and final products offer an interesting alternative to literature procedures.