1,1-Di(9-fluorenyl)ethyl acetate, a by-product from the acetylation of 9-fluorenyllithium

The preparation of sp-9-acetylfluorene from the reaction of 9-fluorenyllith ium with acetyl chloride also provided 9-(1-acetoxyethylidene)fluorene ('di acetylfluorene') and 1,1-di(9-fluorenyl)ethanol, (II), as by-products recen tly characterized by X-ray analysis. A third by-product, 1,1-di(9-fluorenyl )ethyl acetate, (III), C30H24O2, has now been unequivocally identified for the first time, and emanates from the acetylation of the oxyanion of (II). In the asymmetric unit, compound (III) exists as two almost identical struc tures which differ slightly, but significantly, in conformation. Neither po ssesses the significant fluorene-ring bowing or the perpendicularity of the two ring planes exhibited by (II). The angle between the least-squares pla nes of the two fluorene rings of (III) is 58.45 (9) and 60.95 (10)degrees, respectively, for the two conformations, and their corresponding bonding pa rameters also differ slightly in a number of instances.