SYNTHESIS AND RESOLUTION OF THE ENANTIOMERIC TRANS,TRANS-SPIRO[5.5]UNDECANE-1,7-DIOLS AND DETERMINATION OF THEIR ABSOLUTE-CONFIGURATION - (S)-(-)-SPIRO[5.5]UNDECANE-1,7-DIONE

Syntheses of spiro[5.5]undecane-1,7-dione (1) and the three diastereomeric spiro[5.5]undecane-1,7-diols (2, 3 and 4) with cis,cis-, cis,trans- and trans,trans-configuration are described. The structure of the lactone side product (+/-)-5 was elucidated by NMR spectroscopy. Resolution of the trans,trans-diol (+/-)-4 was accomplished via the diastereomeric (1S,4R)-camphanoates (-)-6 and (+)-7 to give (-)-4 and (+)-4. Oxidation of (-)-4 by the method of Swern yielded the optically active dione (-)-1. An X-ray crystal structure of (-)-6 allowed assignment of the absolute configuration of (1R,6S,7R)-(-)-4 and hence of (S)-(-)-1. The chiroptical properties of the bis(4-bromobenzoate) (-)-8 derived from (-)-4 also prove the (1R,6S,7R)-configuration.