Author's Organization：Department of Chemistry, Faculty of Science, The University of Tokyo Department of Chemistry, Faculty of Science, The University of Tokyo Department of Chemistry, Faculty of Science, The University of Tokyo Department of Chemistry, Faculty of Science, The University of Tokyo
On heating with sodium hydrogencarbonate in aqueous methanol, ailanthone (2) afforded 13 (12→11α) abeo-picrasanes [or 9 (11→12α) abeo-picrasanes], shinjudilactone (1) and its 13-epimer (3), in a ratio of 1 : 1 in good yields. The reaction is likely to proceed through isomerization of 2 into an α-diketone (6), followed by benzilic acid rearrangement. Under the same conditions, norquassin (4) gave the rearrangement product, norquassinic acid (5).
