Benzocyclohexadienone derivative

The second salt studied for which conformational bias in the enantiodiffer-entiating step was expected to be small was the benzocyclohexadienone derivative 55. Compounds of this type are known to undergo what is formally an oxadi-7i-methane photorearrangement [44], and salt 55 was no exception, affording cyclopropyl ketone 56 upon irradiation in the crystalline state and diazomethane workup [45]. The ee in which this photoproduct was formed at room temperature was 81% at 25% conversion and 71% at 80% conversion. As usual, lowering the temperature raised the ee (at -78 °C, the ee was 87% at 30%... 

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