Thiocarbonyl ylides heterocyclic synthesis

Synthesis of five-membered S-heterocycles from thiocarbonyl ylides 84BSB511. 

In comparison with other 1,3-dipoles that have been extensively explored in organic synthesis (7), sulfur-centered 1,3-dipoles (1-4) are rather uncommon species. However, within the last two decades, remarkable progress has been made regarding both methods of generation and synthetic applications. In particular, thiocarbonyl ylides (1) were established as key intermediates useful for the preparation of sulfur-containing heterocyclic compounds. General methods for the preparation of thiocarbonyl ylides and their chemical reactivity have been reviewed (8-11). 

Saito et al. <1995S87> described a new method for the synthesis of heterocycle-fused[c]thiophenes via reaction of aryl heteroaryl thioketones with the carbene precursors. Heteroaromatic thioketones A react with carbenoids generated from bis(arylsulfonyl)diazomethanes or phenyliodonium bis(phenylsulfonyl)methylides to give heterocycle-fused[f]thiophenes B. The reaction involves the ring closure of the intermediary thiocarbonyl ylides, followed by restorative aromatization via the elimination of a sulfenic acid (Equation 11). 

The Molecules R2CXCR2 Including Azomethine, Carbonyl and Thiocarbonyl Ylides Their Syntheses, Properties and Reactions R. M. Kellogg, Tetrahedron, 1976,32,2165-2184. Thioureas in the Synthesis of Heterocycles T. S. Griffin, T. S. Woods and D. L. Klayman, Adv. Heterocycl. Chem., 1975,18, 100-158. 

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