Synthesis and photochemical transformations of new butadiene chromophores: The influence of the nature and position of chlorine substituent on the photoinduced behaviour

Functionalization of the benzobicyclo[3.2.1] octadiene skeleton possessing one isolated double bond via photocatalytic oxygenation

“…The proposed mechanism for the formation of the starting substrates involves intramolecular cycloaddition via biradical intermediate followed by preferred 1,6-ring closure and subsequent 1,3-H shift. 13 Bicyclic derivatives 1a-c were obtained as the main products (55-80 % isolated yield) of these reactions.…”

“…12,13,14 Three phenyl derivates, 9-phenyl-, 9-(4-chlorophenyl-, and 9-(4-methoxyphenyl)-tricyclo[6.3.1.0 2 , 7 ]dodeca-2,4,6,10-tetraene (1a, 1b, and 1c, respectively) have been involved in our study: without any substituent (1a), containing a chloro (1b) or a methoxy substituent (1c) in para position. Similarly to our earlier experiments, both anionic and cationic manganese(III) porphyrins Mn (III)TSPP 3-and Mn(III)TMPyP 5+ , where H2TSPP 4-= 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin and H2TMPyP 4+ = 5,10,15,20-tetrakis(1-methyl-4-pyridinium)porphyrin) were applied in order to study the charge effect, beside the influence of the substituent on the phenyl ring.…”

Photochemical Approach to New Polycyclic Substrates Suitable for Further Photocatalytic Functionalization

“…Upon irradiation, mono-and di-α-chloro derivatives 1c and 2c photocyclize to give six-membered ring products 6 and 7. 3 In continuation of our studies on photochemical behaviour of butadiene derivatives we extended research to p-substituted chloro derivatives 1d and 2d. 3 The psubstitution increases molecular planarity, relative to α-substitution and shift conformer equilibrium, affecting the reaction pathways and yields.…”

“…3 In continuation of our studies on photochemical behaviour of butadiene derivatives we extended research to p-substituted chloro derivatives 1d and 2d. 3 The psubstitution increases molecular planarity, relative to α-substitution and shift conformer equilibrium, affecting the reaction pathways and yields. As the main products upon irradiation of p-chloro-butadiene derivatives 1d and 2d new benzobicyclo[3.2.1]octa-diene structures endo-8 and endo,trans-9 are formed in very good yields, with smaller amounts (10 %) of dihydronaphtalene derivative endo-10 in case of 2d ( Figure 2).…”

“…21−27 As a part of our increasing interest in the photochemistry of conjugated butadiene systems and to explore the effect of substituents on the butadiene units on the photochemical reactions, studies are expanded to methyl-and chloro-butadiene derivatives 1b−d and 2b−d. 2,3 Methyl group effects sterically to photochemical reactions, causing diverse photoinduced behaviour and formation of completely different photoproducts. 2 Monosubstituted methyl derivative 1b upon irradiation gives dihydronaphtalene derivative 5 (Figure 2), while disubstituted methyl derivative 2b shows only geometric isomerization.…”