Convenient Synthesis of Methyl 3-Alkynedithioates and β, γ-Unsaturated γ-Dithiolactones from Allenyllithium and Allenylsilver(I) Compounds

Silver Alkyls, Alkenyls, Aryls, and Alkynyls in Organic Synthesis

“…Dimethylargentate is stable in the gas phase, and has been isolated for short periods (10 s) without significant decomposition. 10 Alkylsilver compounds have been prepared by treatment of Grignard reagents with silver salts, [11][12][13][14][15][16][17][18][19] and similarly undergo oxidative homocoupling to give alkyl dimers. [11][12][13]19,20 Exploitation of this finding has resulted in the development of general methodology for silver-catalyzed alkyl-alkyl homocoupling of Grignard reagents (Table 1.1).…”

“…[14][15][16][17][18] The alkylsilver reagents generally reacted with the enynenitriles to give 2,3-alkadienenitriles on protolysis, while homoargentates (R 2 AgMgCl) tended to give 2,4-alkadienenitriles. The homoargentates underwent selective trans addition to the enynenitriles, which is in contrast to the selective cis addition observed for alkylcopper reagents.…”

“…Allenylsilver reagents have been prepared by the reaction of allenyllithium reagents with silver(I) salts, 66,67 and by the addition of alkylsilver reagents to conjugated enynes (see alkylsilver section 1.2.1 above), and have been added to a number of electrophiles in high yield (Scheme 1.24). In most cases, this resulted in allene contaminated with a small percentage of alkyne (<10%).…”

“…In most cases, this resulted in allene contaminated with a small percentage of alkyne (<10%). Carbon disulfide reacted solely at the propargylic position to give b,g-unsaturated g-dithiolactones in excellent yield (Scheme 1.25), 16,68 whereas carbon dioxide reacted at the allenic position to produce allenyl carboxylic acids in good yield. 18 The allenylsilver compound did not react with methyl iodide under these conditions.…”

Unsaturated sulfur compounds from reactions of lithiated methylazines with carbon disulfide and electrophiles

“…The exception is addition to cumulated thiocarbonyl groups, and particularly to carbon disulfide, which is a useful method for preparing dithiocarboxylates (4) and compounds that can be made from them in situ [5][6][7][8], as shown in scheme 1. The products of such reactions, especially the ketenedithioacetals (6) are in turn useful intermediates for further synthesis.…”