Diaryl sulphones synthesis

Geranyl phenyl sulphides or sulphones, Me2C=CHCH2CMe=CHCHXY (33 X = H Y = SPh or SOjPh), cyclized to cyclocitral derivatives under acid conditions, whereas the corresponding dithioacetal (33 X = Y = SPh) gives the thiochroman (34). The novel heterocycles (35) have been prepared by standard methods from the corresponding tellurochromanones. The critical step in the synthesis of the latter consists of reduction of the appropriate diaryl ditelluride with borohydride and subsequent reaction with 3-chloropropionic acid under carefully controlled conditions. 

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