Novel synthesis of trioxatetracyclo[5.3.2.0.^4,9.0^4,11]dodecane and bibenzyl skeletons

A novel 7,9,11-trimethyl-8,10,12-trioxatetracyclo[5.3.2.0.4,9.04,11-dodec-1-yl] -2-butanone skeleton 3 has been synthesized by the treatment of 2-acetyl-3,4-dihydro-2,5-di(3'oxo-butyl)-6-methyl-(2H)-pyran 2, with H-ZSM-5. However, the treatment of compound 2 with p-TsOH gives bibenzyls. Present report provides a unique acid catalysed cyclization of diketo-olefin system over zeolite, X-ray crystal structure of 3 is also presented.