Photochemical Routes to Cyclophanes Invoving Decarbonylation Reactions and Related Process

C. Robbins and Eastman also reported that the decarbonylation proceeds via a two-step mechanism involving the formation of the phenylacetyl radical.

[3.3]Cyclophanes ([3.3]CPs) undergo two types of photochemical reactions, irradiation of the

ππ

* band of multibridged [3

]CPs leads to the formation of polycyclic cage compounds via photocycloaddition of the facing benzene rings, followed by rearrangement of the carbocation species generated by protonation of a cyclobutane ring of the cycloadduct (as described in Chapter 23),

while irradiation of the

n

,

π

* band of [3.3]CP-2,11-diones

undergoes decarbonylation to give [2.2]CPs

in high yields.