The mechanism of the garryfoline-cuauchichicine rearrangement has been investigated using the epimeric (-)kaur-16-en-15-ols as models. The 15s-01 is shown to rearrange rapidly in mineral acid at room temperature to 16R-(-)-kaur-l5-one by a 15,16-hydride shift. The 16a-01, like veatchine, is stable under these conditions.The contrast in the ability of these epimeric alcohols to undergo 15,16-hydride shifts is discussed.Under the same conditions, (-)-kaur-l5-en-I 7-01 gives the allylic isomer, (-)-kaur-l6-en-I 5a-01, but, under more forcing conditions, it yields 16S-( -)-kauran-l7-al.THE diterpene alkaloid, garryfoline (I), is rapidly rearranged to cuauchichicine (11) in dilute mineral acid at room temperature. A similar rearrangement has been observed in the diterpene alkaloids , napelline ,2 kobusineJ3 and atisine,* and recently in the (-)-kaurene derivative (VII; R = H, 19-C0,H).5 The generality of the rearrangement has been demonstrated with the monocyclic allylic alcohols (111; n = 1 or 2) and (IV; n = 1 or 2) which, under more forcing conditions in the presence of 2,4-dinitrophenylhydrazine, gave the DNP derivatives of the ketones (V; n = 1 or 2).

The ability of acetylenic systems to participate in intramolecular reactions proceeding via six-membered cyclic transition states has been established by thermolyses of a number of substituted /3-hydroxyacetylenes, in both the vapor and the liquid states. Thermolyses products consisted solely of those alienes and carbonyl compounds derivable from a 1,5-hydrogen transfer. The homogeneous reactions followed the first-order rate law. Activation energies with a variety of alkyl substituents were essentially within experimental error.

Electrocyclic ring closure of a,0-cM-l,3-pentadienyl isocyanate affords 3-methy 1-2(lfl-)-pyridone in fair yield. The isocyanate is formed in good yield by treatment of sorboyl chloride with trimethylsilyl azide in refluxing toluene. In refluxing heptane this reaction affords tetrazolinone 6 rather than isocyanate. The sensitive pentadienyl isocyanate is converted to polymer by either pyrolysis or acid treatment.

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the catalytic hydrogenation, and Dr. George Lenz for the helpful discussions and assistance with the photochemical reactions described.