Carbophilic addition with Grignard reagents

Unlike selenobenzophenone, 4 reacts with alkyllithium to afford mainly the corresponding carbophilic adducts, and with Grignard reagents, compounds resulting from addition of the organic radical to sulfur. 

With allylic Grignard reagents, the carbophilic addition on the thiocarbonyl of phenylisothiocyanate occurred as expected exclusively with inversion of the allylic chain. From crotyl and prenyl magnesium halides the compounds (4f) and (4g) were obtained in yields of 77 and 72%, respectively. 

Further examples of thiophilic addition of methyllithium and carbophilic addition of allyl- or benzyllithium and allyl Grignard reagents with 1,3-thia-zole-5(4ff)-thiones were reported [143]. Perfluorodithioesters were reacted with alkylmagnesium bromides, providing a new entry to perfluoroketene... 

Carbophilic addition of prenylmagnesium bromide and other allylic Grignard reagents to the thiocarbonyl group of dithioesters occurs exclusively with rearrangement of the allylic... 

Reactions of different organometallic species with thiocarbonyi compounds have been extensively investigated and been shown to proceed both in a carbophilic and a thiophilic fashion. However, other reactions can be observed simultaneously such as reduction, double addition, coupling, deprotonation and formation of enesulfides1,226,423. A complex pattern appears in the reactions of thioketones with lithium or Grignard reagents424. The first application of Reformatsky reagents in C—C bond formation by reaction with... 

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