PREPARATION OF ALKYLIDENECYCLOBUTANES AND THEIR TRANSFORMATION TO 2,2-DISUBSTITUTED CYCLOPENTANONES

The reaction of ketones with the titanocene reagent prepared by the tr eatment of 1,1-bis(phenylthio)cyclobutane with the low valent titanium species Cp2Ti[P(OEt)(3)](2) produced the corresponding alkylidenecycl obutanes. These compounds were successfully transformed into 2,2-disub stituted cyclopentanones by the epoxidation and subsequent ring enlarg ement. The similar reactions of the carbene complexes with carboxylic esters and thiolesters also proceeded to afford (1-alkoxy- and alkylth io-alkylidene)cyclobutanes, respectively, in good yields.