Sequential Functionalisation of Bis-Protected Tetrathiafulvalene-dithiolates

All articles of this category The utilisation of the 2-cyanoethyl group as a versatile protecting group for 2-thioxo-1,3-dithiole-4,5-dithiolates and tetrathiafulvalene-thiolates is reported. Mono deprotection of bis-protected 2-thioxo-1,3-dithiole-4,5-dithiolate and of bis-protected tetrathiafulvalene-2,3-dithiolates [obtained by cross coupling of 4,5-bis(2-cyanoethylthio)-1,3-dithio-2-one 5 and the 1,3-dithiole-2-thiones 2b-h and 2j in triethyl phosphite] was achieved in very high yields. The monothiolates were generated from the bis-protected starting materials by selective mono deprotection in dimethylformamide solution using one equivalent of caesium hydroxide monohydrate in methanol. Subsequent quenching with iodomethane gave the resulting methylthio-substituted 1,3-dithiole-2-thione 2i and tetrathiafulvalenes 8 in near quantitative yield. The X-ray crystal structure of the air-stable caesium tetrathiafulvalene-thiolate 10 is reported. This is the first single crystal X-ray structure determination of a tetrathiafulvalene-thiolate. tetrathiafulvalene - π -donor - cross coupling - selective deprotection - stable caesium thiolate salt