Synthesis and crystal structure of 5-carbaphosphatranes containing a four-membered cycle

4,4-Bis(trifluoromethyl)-4,5-dihydro-2-phenylbenzo[e]- and 4,4-bis(trifluoromethyl)-4,5-dihydro-2-phenyl-(4'-chlorobenzo)[e]-1,3,2-dioxaphosphepin-5-ones react with hexafluoroacetone to form unusual propeller type structures – 3,3,10,10-tetrakis(trifluoromethyl)-1-phenyl-6,7-benzo- and 3,3,10,10-tetrakis(trifluoromethyl)-1-phenyl-6,7-(4'-chlorobenzo)-2,4,8,9-tetraoxa-1-phosphatricyclo[3.3.2.0^1,5]decenes (5-carbaphosphatrane derivatives), the structure of which has been determined by NMR spectroscopy and single crystal X-ray diffraction analysis.