87161-00-0Relevant academic research and scientific papers
cis,trans-Oxaaza-bis-?-homobenzenes - 4H-1,4-Oxazocines
Mueller, Klaus-Helmut,Kaiser, Clemens,Pillat, Michael,Zipperer, Bernhard,Froom, Manfred,et al.
, p. 2492 - 2523 (2007/10/02)
The cis-oxaaza-bis-?-homobenzene framework has been synthesised via two routes starting from readily accessible materials (11, 25).As expected the N-SO2R derivatives 3a,b are sufficiently stable to be isolated; on heating, they readily and quantitatively undergo ?2 + ?2 + ?2>-cycloreversion to the 4H-1,4-oxazocines 6a,b (3b: t1/2(60 deg C) = 33.2 min; ΔG* = 104.0 kJ*mol-1).The latter prefer a non-planar, folded conformation.Using a precursor of 3b (27a), the thermally stable trans-oxaaza-bis-?-homobenzene 9 was obtained in very small yield (2 - 6percent) by two alternative pathways.
