Cyclooctatetraene epoxide

The thermal isomerization of cyclooctatetraene epoxide has been studied at 260 by Bttchi and Burgess,who observed the formation (if thtoo isomerio eJdehydos f Eq. 460a), one cf whidi may be the elueive compound noroaradieno csrboxaldehyde. 

The fleeting cis, trans azonine rotamers (86) and (87) were shown through cycloaddition (see following section) to intermediate the thermal isomerization of (88) to (89) (73JOC1959) and were conjectured to cyclize, respectively, to these [5.2.0] frames via symmetry-allowed 4a processes. Further, the thermal isomerization of the urethane analog of (88) and low-temperature irradiation of cyclooctatetraene epoxide (85a) to frans-fused [4.3.0] frames (91a) and (91b) respectively were hypothesized to arise by internal 6s pericyclization of a fleeting mono-frans (f,c,c,c) heteronin frame (90) (75PAC(44)69l). 

The irradiation of cyclooctatetraene epoxide (58) in pentane or methanol with unfiltered light led only to rapid polymerization 42). 

Cyclooctadiene-1,5, 23, 62, 445 Cyclooctane-1,2-diol, 384 Cyclooctane-1,5-diol, 64 Cyclooctanol, 183 Cyclooctatetraene, 23 Cyclooctatetraene epoxide, 306, 519 Cyclooctatetraeneiron tricarbonyl, 567 Cyclooctene, 23, 183, 445 Cyclooctene oxide, 334 Cyclooctyl fluoride, 183 Cyclopentadiene, 123, 291 Cyclopentadienone, 454 iT-CycIopentadienylcobalt dicarbonyl, 153-154... 

The existence of a metalated epoxide was first proposed by Cope and Tiffany, to explain the rearrangement of cyclooctatetraene oxide (8) to cydoocta-l,3,5-trien-7-one (11) on treatment with lithium diethylamide. They suggested that lithiated epoxide 9 rearranged to enolate 10, which gave ketone 11 on protic workup (Scheme 5.4) [4],... 

Moreover, in the same work, the 0-labeling experiment confirmed chiral dioxiranes to be the intermediates in chiral ketone-catalyzed epoxidation reactions. Murray et al. reported the synthesis and structural characterization of cyclooctatetraene tetraepoxides 90 and 91 through the oxidation of cyclooctatetraene with excess of DMDO lb... 

Although they are sometimes utihsed for their nucleophihc properties, as out-hned above hthiated epoxides are carbenoid species, and they are well known to react through C-H and C=C insertion or 1,2-shift processes. Following his early studies on cyclooctatetraene oxide. Cope extended his work to stilbene derivatives 58 and 60 (Scheme 10) [47]. The ketone 59 and aldehyde 61 were derived from (formal) 1,2-shift of the group (either H or phenyl, respectively) cis to hth-ium on the lithiated epoxide. 

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