MOORE Cyclobutenone Rearrangement

MOORE Cyclobutenone Rearrangement Thermal rearrangement of alkyl or alkenylcyclobutanones to benzofurans, quinones,... 

In another example from Moore, cyclobutenone 148, rearranges to give enyne-ketene 149. The resulting diradical was intercepted by a tethered alkyne, which in turn led to spirocycle 153 (Scheme 27) [49],... 

Moore et al. investigated the thermal rearrangements of differently substituted cyclobutenones. Reactions of 4-alkenyl-4-hydroxycyclobute-nones such as 18, in which the triple bond is replaced by a double bound, are complementary to the ring expansions of 4-alkynyl-4-hydroxycyclobute-nones and provide a route to the differently substituted benzoquinones, such as aurrantiogliocladin 19. The reaction proceeds via enyne-ketene 20. Since cyclization produces a derivative of hydroquinone 21, an additional oxidation step is required that is accomplished with the use of cerium ammonium nitrate on silica. This ring expansion process is independent of the... 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

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