By Cycloadditions involving Thiocarbonyl Compounds

By Cycloadditions involving Thiocarbonyl Compounds. The photocatalysed cycloaddition of thiocarbonyl compounds to olefins to form thietans has been reviewed. The photo-addition of thiobenzophenone to cis- and /m j-dichloroethylene and to cw-dicyanoethylene apparently proceeds with retention of configuration in the olefin moiety. Allenes participate in such reactions, thiobenzophenone with tetramethylallene and methoxy-allene, for example, giving the thietan derivatives (44) and (45). Thiobenzophenone in its triplet excited state apparently attacks the central 

Kumakura, T. Shimozawa, Y. Ohnishi, and A. Ohno, Tetrahedron, 1971, 27, 767. H. Gotthardt, Tetrahedron Letters, 1971, 2345. 

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