Oxepine and fused derivatives

Piccialli reported the extenstion of ruthenium-catalysed oxidative cyclisation of dienes 54 to yield 2,7- disubstituted trans-oxepane diols 55 07TL5131 . 

A synthesis of the pine beetle pheromone isolaurepan 58 was reported by the elaboration of the a-benzyloxyalkenal 56 to the co-hydroxy ketones 57 before cyclisation to the target 07TA1419 . 

The chiral enamide 59 was reported to undergo halo-etherification to yield the brominated oxepine 60 with 20 1 diastereomeric ratio 07OL4459 . The same methodology was also extended to 1,4-dioxazepines. 

Many examples of carbohydrate analogues 63 have been reported including the ring opening of fused gem-dibromocylopropanes 61 to give alkenyl bromides 62 that can be elaborated further 07JOC5500 . 

Nucleosides based upon monocyclic, fused and spirocyclic oxepines have been synthesised via nitrone cycloaddition reactions 07JOC7427 , while oxepine nucleic acids were synthesised from the ring expansion of cyclopropanated glycals 07JACS8259 . 

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Relatively few significant papers appeared on oxepine systems or fused derivatives. Rearrangement processes were commonly involved in their synthesis. For example, treatment of 89 with n-BuLi and then methanesulfonyl chloride afforded the oxepine 90 as a dark red solid in good yield via rearrangement of the intermediate substituted benzene oxide derivative <05TL3221>. 

Reactions of Fused Azepines. The morphanthridene derivative (40) undergoes an interesting rearrangement to (42) when treated with primary amines the reaction involves a transamidation which converts (41) into (42). Reversal, with concurrent reduction of the carbonyl, is induced by lithium aluminium hydride. The diarylethylene-type double-bond in some dibenz-azepines and -oxepines can be reduced conveniently and in high yield, using magnesium in methanol. 

A single quinolone-fused oxepine 45 was reported in a study on the gold (I)-catalyzed formation of functionalized quinolones (130L4234).The starting 2-alkynylarylazide derivatives such as 44 undergo a 1,3-acetoxy shift, followed by cyclization of the azide and a ring-expansion via a 1,2-shift. 

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