Cyclooctatetraene monoepoxide

Matsuda and Sugishita found that cyclooctatetraene monoepoxide (233 equation 99) gave only skeletally rearranged products, e.g. (234), when treated with Grignard reagents. In an effort to isolate the presumed intermediate cycloheptatrienecarbaldehyde, (233) was subjected to a catalytic amount of MgBra, but this resulted in the formation of phenylacetaldehyde. 

The parent system oxonin (1) is generated by benzophenone sensitized irradiation with a Hanovia light source3 5 or direct irradiation6 of the monoepoxide of cyclooctatetraene (9-oxabicyclo[6.1.0]nona-2,4,6-triene, 6). 

This reaction has been applied" to 9-oxabicyclo(6.1.0]nona-2,4,6-triene (4), the monoepoxide of cyclooctatetraene. This substance is converted in 70% yield into (5), by way of the lactone (a) and the Fe(CO)3 complex (b). Decomposition of (5) with trimethylamine oxide (this volume) gives the hitherto unknown 9-oxabicyclo[4.2.1 ]nona-2,4,7-triene (6). 

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