Cyclopentenones, Ramberg-Backlund reaction

An example of sulfinate functioning as a leaving group is shown in equation (16), ° while another forms the basis of a useful synthesis of 3-cyclopentenones (Scheme 22). Zwanenburg has reported a transformation related to the Ramberg-Backlund reaction in which the halide leaving group is replaced by sulfinate and, in addition, the usual sulfone is replaced by sulfoxide. ... 

Since the late 1970s, the Ramberg-Backlund reaction has been used to convert a wide variety of six-membered cyclic a-halo sulfones into cyclopentenes, often in high yield and useful regioselective syntheses of both 2- and 3-cyclopentenones, using sequences in which the Ramberg-Backlund reaction is the key step, have also been reported. Bu OK in THF, diethyl ether or DME are the preferred conditions for these reactions and, in addition, Meyers method has been used to convert six-membered cyclic sulfones directly into cyclopentenes. Examples of these reactions follow. 

A new cyclopentenone synthesis has been described which uses the Ramberg-Backlund reaction of the sulphone (18), which is derived... 

Chem. Lett. 1984, 833-836. For another variation of the Ramburg-Backlund reaction see Matusuyama, H. Miyazawa, Y. Kobayashi, M. Regioselective Alkylation and the Ramberg-Baecklund Type Reaction of a-( -tolylsulfonyl)thiane S,S-Dioxide. A New Route to the Synthesis of 3-Alkyl-3-Cyclopentenones Chem. Lett. 1986, 433—436. 

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