Photochemistry of 1‐Methoxybicyclo[2.2.2] octenones; Photolytic Cyclopropane Cleavage of the Initially Formed Tricyclo [3.3.0.0^2,8]octan‐3‐ones

Abstract

Rotational strengths calculated on the basis of this structure"' agree well with the experimental values and support our model. The available data do not allow, at this time, a decision to be made as to whether other equilibria, apart from the dimerization, are involved in the formation of the aggregate. The factors that are responsible for the remarkable chirdl discrimination and the stability of this system are the subject of further study.

Synthetic Aspects of the Di-π-methane Rearrangement

“…Thus, a key step in the synthesis of the hydroxylsubstituted [3] 114,115 Thus, under these conditions, compound 122 gives the 1,4-diketone 123 in 75% yield. 115 To account for this result, a mechanism has been proposed consisting in the ODPM rearrangement of 122 to 124, followed by photolytic (129) are another type of compounds that undergo efficient ODPM rearrangement to tricyclooctadiones (130). These reactions have found interesting applications in the synthesis of natural products such as (-)-coriolin 123 and cedranoid sesquiterpenes.…”

“…[109][110][111][112][113][115][116][117][118][119][120][121][122] However, it should be pointed out that there are limitations in the type of substitution that can be present in the bicyclo[2.2.2]-octenone skeleton. Demuth has summarized the influence of substitution by electron-acceptor and electron-donor groups on the outcome of the reaction.…”

Intramolecular Photoreactions of 9-Cyanophenanthrene-Linked Arylcyclopropanes

“…Pale yellow solid; mp 106−107 °C; 1 H NMR (400 MHz, CDCl 3 ): δ 0.91 (dt, J = 8. 5,5.4 Hz,1H),0.96 (dt,J = 8.3,5.1 Hz 1H),1H),1.77 (dt,J = 8.5,5.1 Hz,1H),3.58 (dd,J = 10.4,6.8 Hz,1H),3.62 (dd,J = 10.2,6.6 Hz,1H),5.22 (s,2H),5H) (100 MHz, CDCl 3 ): δ 13. 9, 21.2, 22.2, 68.4, 73.5, 110.1, 116.3, 122.3, 122.4, 125.2, 125.9, 126.2, 127.1, 127.6, 127.7, 127.8, 127.9, 128.6, 129.0, 129.4, 131.0, 140.0, 141.9 85.92;H,5.82;N,3.85.…”

“…To date, studies of [3 + 2] photocycloaddition reactions of cyclopropanes with alkenes have focused on processes involving the additions of methylenecyclopropanes to tetracyanoethylene, 2 triarylcyclopropanes to vinyl ethers, 3 vinylidenecyclopropanes to electron-deficient alkenes, 4 and tricyclo[3.3.0.0 2,8 ]octan-3-ones to 2-trimethylsiloxybutadiene. 5 In addition, intramolecular photoreactions of pentacyclo[6.3.1.1 3,6 .0 2,7 .0 9,11 ]tridec-4-ene 6 and photocatalytic [3 + 2] cycloaddition of benzoylcyclopropanes with alkenes in the presence of Ru catalysts and Lewis acids 7 have been probed. However, only a few reports exist which describe the photoreactions of cyclopropanes with arenes.…”

“…We envisioned that cyclopropane derivatives would be interesting replacements for the unsaturated compounds employed in these photocycloaddition reactions because they would serve as precursors of C3 units in the generated polycylic products. To date, studies of [3 + 2] photocycloaddition reactions of cyclopropanes with alkenes have focused on processes involving the additions of methylenecyclopropanes to tetracyanoethylene, triarylcyclopropanes to vinyl ethers, vinylidenecyclopropanes to electron-deficient alkenes, and tricyclo­[3.3.0.0 2,8 ]­octan-3-ones to 2-trimethylsiloxybutadiene . In addition, intramolecular photoreactions of pentacyclo­[6.3.1.1 3,6 .0 2,7 .0 9,11 ]­tridec-4-ene and photocatalytic [3 + 2] cycloaddition of benzoylcyclopropanes with alkenes in the presence of Ru catalysts and Lewis acids have been probed.…”