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Organometallic Compounds as Heterogeneous Catalysts
Published in Varun Rawat, Anirban Das, Chandra Mohan Srivastava, Heterogeneous Catalysis in Organic Transformations, 2022
Garima Sachdeva, Monu Verma, Varun Rawat, Ved Prakash Verma, Manish Srivastava, Sudesh Kumar, Singh Vanshika
Allenes are the organic compounds in which one carbon atom has double bonds with the two adjacent carbon centers. They are categorized as cumulative dienes. Varghese and the group had described the method for synthesizing substituted allenes that are further used to synthesize chiral compounds. Carbocupration of alkynyl sulfoxide, followed by homologation of vinyl copper with zinc carbenoid, lead to the formation of allyl zinc derivative that further undergoes β-elimination to form substituted allene (Figure 4.27) [52].
Reactions of thiocarbonyl compounds with electrophilic and nucleophilic carbenes as well as with their metal complexes
Published in Journal of Sulfur Chemistry, 2020
Grzegorz Mlostoń, Heinz Heimgartner
Another method to generate reactive thiocarbonyl ylides comprises the electrophilic attack of a two-valent carbene 8 or carbenoid onto the electron-rich sulfur atom of the C = S group. Diazomethane derivatives are known as the most important source of carbenes/carbenoids, which are formed upon heating, photolysis or by metal-assisted decomposition. It is well established that diazomethanes, functionalized at the α-position with electron withdrawing groups, display reduced reactivity as 1,3-dipoles, and in most cases their reactions with thiocarbonyl groups require the involvement of a catalyst to change the reaction type from the [3 + 2]-cycloaddition to the electrophilic approach of the carbene. The formation of thiocarbonyl ylides can also be achieved when reactive carbenes are generated from other precursors, e.g. dichlorocarbene from chloroform in a two-phase system or by thermal decomposition of Seyfert's reagent (PhHgCCl3).