Planarisierung von tetrakoordiniertem Kohlenstoffatom. Synthese des überbrückten all-cis-[5.5.5.5]Fenestrans 13-Oxapentacyclo[5.5.2.11.7.04,15.010,15] pentadecan-14-on

Planarisation of Tetracoordinate Carbon Atom, Synthesis of the Brigded all-cis-[5.5.5.5]Fenestrane 13-Oxapentacyclo[5.5.2.1^1,7.0^4,15.0^10,15]pentadecan-14-one The synthesis of the ketolactone 23 from (Z,Z)-1,5-cyclooctadiene is reported. Transannular carben insertion, achieved via photolysis of the deprotonated (2,4,6-trisisopropylphenylsulfonyl)hydrazone of 23 gives the bridged all-cis-[5.5.5.5]fenestrane 3 .