Photochemical Experiments with 2,3‐Bis(Tert‐Butylsulfonyl)Bicyclo[2.2.2]Octa‐2,5‐Diene and Related Systems

Abstract

The irradiation of 2,3-bis(tert-butylsulfonyl)norbomadiene (5) and 2-(tert-butylsulfony1)norbomadiene (6) yielded the expected quadricyclane derivatives as stable molecules. The Irradiation of 2,3-bi·;(tenbutyIsulfonyl)bicyclo[2.2.2]octa-2,5-diene (7), 2, .2]-octa-2,5-diene (8) and 8,9-bis(tert-butylsulfony1)-4-anti-phenyl-3,5-dioxa-exo-tricycJo(5.2.2.0 2 ,6] undeca-8, IO-diene 9a and its syn-isomer 9b yielded the corresponding tetracyclic and pentacycHc systems, respectively. The photoproducts of 8 and 9 reverted to the starting products slowly at room temperature, The halflife of the photoproduct of 7 was determined to be 34 min at 50·C, Compound 9a reacted with n-BuLi to yield the unexpected desulfonylation product 27a.The photochemistry of norbornadiene and many substitution products has been investigated in great detail, in and the methylene chain bridging the 2,3-positions of 2. This is supported by X-ray investigations on single crystals of 2. 3• However, if one tert-butyl-sulfonyl group in 2 was replaced by H, D, or CH 3 we found again prismane formaLion when the sample was irradiated." This difference in the behavior as a function of the substitution pattern made us look more closely at the photochemistry of the next higher sulfonyl substituted homologues of Dewarbenzenes, i.e. 2, -diene (9a) and its syn-isomer 9b.~S

Norbornadiene–quadricyclane as an abiotic system for the storage of solar energy

“…Two substituents of the same nature shift the l ae value only slightly towards the solar radiation maximum. 59,60 For example, the absorption of 2,3-di(tert-butylsulfonyl)norbornadiene ( 16) is characterised by a slight bathochromic shift with respect to the maximum absorption of nonsubstituted NBD 1, although the 16 ? 17 isomerisation occurs quantitatively in ether under irradiation with light with l irr > 280 nm.…”

Synthesis, characterization and computational evaluation of bicyclooctadienes towards molecular solar thermal energy storage

“…15 However, several examples of BODs and the corresponding TCOs have been isolated and reported in the literature . [15][16][17][18] For example, Gleiter et.al 19 described the formation of TCOs (Figure 2). The methyl estersubstituted (8) could not be isolated but proven by trapping with HCl, while 9 containing an epoxide functionality, could be isolated at 0 o C. TCO (10), with trifluoromethyl groups, was found to be more stable, with a half-life of 5.5 minutes at 80 o C. 19…”

“… 15 However, several examples of BODs and the corresponding TCOs have been isolated and reported in the literature. 15–18 For example, Gleiter et al 19 described the formation of TCOs ( Fig. 2 ).…”

“…TCO (10), with trifluoromethyl groups, was found to be more stable, with a half-life of 5.5 minutes at 80 °C. 19 …”

“…ethyl propiolate(19) was brominated with NBS to produce ethyl 3-bromopropiolate (20) (Scheme 2). Thereafter, 20 was reacted in a Diels-Alder reaction at 60 o C with cyclohexadiene to afford ethyl-3-bromobicyclo[2.2.2]octa-2,5-diene-2-carboxylate (21) in a yield of 71%.…”