2.4- Benzoxazocine derivative

The transition metal catalysed nucleophilic attack of heteroatoms onto triple bonds has also been exploited in the preparation of larger rings. The intramolecular reaction of the phenol derivative shown in 5.12. and the pendant triple bond could result in the formation of a seven or an eight membered ring. Although the former system would be favoured by geometric considerations, the only product formed in the process is the benzoxazocin derivative, whose formation is probably driven by electronic factors.12... 

Regarding the 1,3-oxazocines, it was reported that the isolation of 5, 8-anhydro-adenosine in an attempt of obtaining 8-fluoroadenosine <2007T3782>, a decaline-fused 1,3-oxazocine, which was unexpectedly obtained in the contest of an attempted synthesis of axinyssamine <2007T1544>, an efficient synthesis and X-ray crystal structure analysis of [ 1 ]bcnzopyrano[4,3-r/]l,3-benzoxazocin-13-onc and its derivatives and 5,6-dihydro-2,4-... 

IR spectra of the 2-ones ((43) and (44) X = O) display the anticipated urethane carbonyl band at ca. 1700-1740 cm <85BCJ2855, 90HCA739>, while the less-reduced derivatives for which IR data has been reported, (45) and 5,6-dihydro-I/f-2,4-benzoxazocines (46) and (47), display intra-ring C=N modes near 1655 cm <65JCS4014,78TL2087>. 

A -Formyl-l/f-3,4,5,6-tetrahydro-l-phenyl-2,5-benzoxazocine (76 R = CHO) is reduced to the A -methyl derivative by sodium borohydride <82AJC2307>. Similarly, A -acyl derivatives of this benzoxazocine are r uced by lithium aluminum hydride to the corresponding alkyls <84JAP(K)59I3769>. 

Sommelet-Hauser rearrangement of the nitrogen ylide formed upon desilylation of oxazolinium derivatives affords benzoxazocines (67) and/or their putative tautomers (84) in low to modest yield... 

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