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This report was prepared m an account of GoTremment sponsored work. Neither the United Stales, nor the Commission, nor any person acting on behaif of tte CJommlssloffi A. Maltes any wananty or representation, expressed or Implied, with respect to the accuracy, completeness, or asefatoess of the information cont^ned in Ms report, or that the ase of any information, apparatus, method, or process disclosed in this report may not infringe privately owned tights: or B. Mstimes any Eabilittes with respect to the use of, or for damages resulting from the use of say information, appiratus, method, or process disclosed in this report. As ased in the above, "person acting on behalf of the Commission" Includes any employee or contractor of toe Commission, or employee of such contractor, to the extent that sttch employee or contractor of the Commission, or employee of such contractor prepares. disseraiaates, or provides access to, any information pursuant to Ms employment or contract with the Commission, or Ms employment with such ctmtractor.

The self-condensation of cyclohexanone in diethyl ether catalyzed by sodium amide has been found to provide a one-step route to pyran 3. Evidence is presented that the Cornubert ketone formed by this reaction corresponds to ketol 2 which readily rearranges under dehydrating conditions to afford pyran 3. Structural elucidation of pyran 3 was achieved by a combination of degradative (3 → 5b), synthetic (8 → 5b), and spectral methods. Xanthene 7, a key dehydrogenation product of ketol 2, was converted by selective reduction to dihydropyran 5b. The five-step synthesis of dihydroxypyran 5b from 1-carbomethoxycyclopentanol (8) provided unequivocal evidence for the structure assigned pyran 3 and xanthene 7.