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.
据报道,2-
氰乙基是 2-
硫酮-1,3-二
硫环戊-4,5-二
硫酸盐和四
硫富
戊烯-
硫酸盐的多功能保护基团。通过 4,5-双(2-
氰乙基
硫代)-1,3-二
硫代-2-酮 5 与 1,3-二
硫代-2-
硫酮 2b-h 和 2j 在
亚磷酸三乙酯中的交叉偶联,实现了双保护的 2-
硫酮-1,3-二
硫代-4,5-二
硫酸盐和双保护的四
噻吩富
戊烯-2,3-二
硫酸盐的单脱保护,产率非常高。在二甲基甲酰胺溶液中,使用一
水合
氢氧化铯在
甲醇中进行选择性单脱保护,从双保护起始材料中生成单
硫醇酯。随后用
碘甲烷淬火,得到甲
硫基取代的 1,3-二
硫杂-2-
硫酮 2i 和四
硫杂
戊烯 8,产量接近定量。报告了空气稳定的四
硫富
戊烯硫代
铯 10 的 X 射线晶体结构。这是首次测定四
硫富
戊烯硫酸盐的单晶 X 射线晶体结构。