Oxepines and fused derivatives

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 . 

Rhodium (Il)-catalysed [3+4] cycloaddition of the diazodiketone 91 to 1,3-pentadiene 92 gave the fused oxepine 94 in moderate yield plus the 5-membered ring derivative 93 

Formation of the fused cyclopropane 96 from 95 by carbene cycloaddition, and subsequent TFA-mediated ring expansion provided access to the 1-benzoxepines 97 in low to moderate 

The 1-benzoxepinone 101 has also been reported and was made by a concise tandem ring opening (of the oxazole moiety in 100) and a cyclocondensation process affording 101 in good overall yield 05SL259 . Standard methodology was used to access 100 from 98 via 99. 

The single crystal X-ray structure of the enantiopure tetrahydro oxepin-2-one 61, a mimic of steroidal androgens, has been reported 06ZN(B)111 . A new procedure has been described for the synthesis of substituted furano-fused oxepines based on expoxidation of strained fused cyclobutenes followed by thermal rearrangement 06OL5183 . 

A new and useful route to the 3-benzoxepin-2-one 64 involved coupling of the Fischer carbene 65 to the epoxy phenylacetylene 62 to give 64 (46%) via 63. An epoxyvinylcarbene complex is proposed for the initiation of the reaction followed by CO insertion and cyclisation 06H(67)233 . 

A tandem palladium-catalysed ort/io-alkylation/intramolecular Heck reaction coupling sequence was used effectively to access in fair yields the tetrahydro 1-benzoxepines 67 from the iodoaryl precursor 66 and the appropriate alkyl bromide. The norbornene plays a relay role in the proposed reaction cycle 06JOC4937  

A new BF3-induced stereospecific rearrangement of the epoxy ethers 68 gave the enantiopure tetrahydro 2-benzoxepin-4-ols 69a, b in generally good yields 06JOC1537 . The enantiomerically enriched compounds 69c,d were also produced. 

Ring-closing metathesis has been used effectively to prepare the pyrido[3,2-h oxepine derivative 71 in good yield from the pyridyl diene precursor 70 06TL6235 . 

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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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