An alternate route for the conversion of dithia[3.3]cyclophanes to cyclophane-dienes. Reaction with benzyne followed by sulfoxide pyrolysis.

Condensed Benzenoid Cyclophanes

“…Naphthalene and benzene do not normally show much reactivity toward singlet oxygen. The deshielding effect of the naphthalene ring on the vinyl protons is even greater than that in [2.2]paracyclophane-l,9-diene 45 and [2.2.2](l,3,5)cyclophane-1,9,17-triene. A second internal Diels-Alder reaction would convert 42 to 43, which under solvolysis by methanol produces 41.…”

“…Ring contraction of 160 gave good yields of the [2.2]cyclophane 163. An alternative route to diene 165 159 employed the benzyne-Stevens rearrangement procedure 45 and commenced with compound 158. 98 ' 99 -158 The diene 165 was made 157 by subjecting 158 to a Wittig rearrangement, 17 oxidizing the resulting product to a disulfoxide, and effecting a thermal elimination of methylsulfenic acid.…”

The synthesis and reactions of 2,11-diselena[3,3]metacyclophanes. An investigation of the selenoxide elimination route to metacyclophane-1,8-dienes

“…and Boekelheide (9) have shown that sulfoxides Dithiacyclophanesl have attracted much atten-1Kb and 1Ka give d i h~d r o~~r e n e 3b (34%) and tion in recent years both because of their interesting PYrene 4 (37%) respectively on pyrolysis under fluxional properties (1) and because of their ready vacuum. The internal hydrogen substituents of the conversion into both the cyclophanes themselves initially formed 3a were evidently lost at the tem-(2) and into many novel derived polycyclic aroma-perature of the pyrolysis-Indeed it has been shown tic compounds (3).…”

Bridged [18]annulenes. A study of the synthesis and properties of 12c,12d,12e,12f-tetrahydrobenzo[g,h,i]perylene and its analogs

“…The course of the photocyclization could readily be followed by N M R monitoring and, with the exception of the two examples (Id and If) having internal methyl groups, the photostationary state corresponded to complete, or nearly complete, conversion to the bridged [ 18]annulenes. In the event, irradiation of solutionsof eachof the cyclophanedienes la-f in perdeuteriotetrahydrofuran caused a change in color to deep orange or reddish orange, and the N M R spectra of the irradiated solutions showed new signals at both higher and lower field than those of the starting cyclophane dienes.…”

“…The N M R chemical shifts for the internal protons of the various bridged [ 18]annulenes are summarized in Table I. Examples 2a, 2b, 2c, and 2d, where R = -H, show the four internal protons as an AA'BB' multiplet broadened a bit by long-range coupling with the peripheral aromatic protons.…”