1.3- Dithiole-2-iminium salts

Reduction of the iminium salt 172 with NaBHa led to formation of the 4-methyl-l,3-dithiole derivative 173, which upon treatment with AC2O, HPE, and then Nal afforded 174, then reacted with triethyl phosphite to form the phosphonate 175 (Scheme 18) <2000EJ051>. 

Amino-l,2-dithiolium salts are obtained from either / -oxocarbox-amides or ) -oxocarbonitriles by reaction with phosphorus penta-sulfide, followed by addition of perchloric acid (Scheme 6). These cations, which may also be considered as iminium salts, are deprotonated to the corresponding l,2-dithiol-3-imine by ammonia. ... 

Reduction of 2-iminium-l,3-dithioles 169 with NaBH4 and futther deamination using HPE gave 2-dimethylamino-1,3-dithioles 170 and the 1,3-dithiolium salts 171, in turn (Scheme 17) <2004EJ01455>. 

Phosphonates based on (1), i.e., (PI), can be prepared simply by heating 1,3-dithiole-2-thiones with a trialkyl phosphite at high dilution [215]. They react with aldehydes, ketones, 2-iminium-I,3-dithioles or dithiolium salts and selenium analogs to give larger molecules, precursors of extended tetrachalcogenaftil-valenes (see below). The reactions take place in the presence of a base, such as butyllithium (BuLi) or LDA. Some aldehydes and ketones, which have... 

---