1.2.3- Benzoxathiazine

Benzoxathiazine 2,2-dioxides 9 do not possess aromatic or antiaromatic character and are therefore only discussed briefly. Compounds 9 can be synthesized by cyclization of 2-hydroxy-aryl ketones with sulfamide or chlorosulfonyl isocyanate.28-30... 

Steroidal 1,2,3-oxathiazines 225 were prepared from substrate 224, and 1,2,3-benzoxathiazines 227 from 226 (Equations 63 and 64) <2003ST97, 2005JA15391>. 

The Diels-Alder cycloaddition of chiral cyclic 2-amidodienes, derived from chiral a-allyl allenamides, with enones yielded optically enriched [2.2.2]bicyclic adducts with dr up to >95 5. In the presence of HOMO-raised trienamines, e-deficient l-aza-l,3-butadienes containing 1,2-benzoisothiazole-1,1-dioxide or 1,2,3-benzoxathiazine-2,2-dioxide react as dienophiles in normal-electron-demand Diels-Alder reactions rather than the corresponding inverse-electron-demand versions. The Fe(III)-catalysed benzannulation of 2-(2-oxyethyl)-benzaldehydes with alkynes produced naphthalene derivatives in high yields (99%) under mild reaction conditions. ... 

A new method has been reported for the preparation of 1,2,3-benzoxathiazine-2,2-dioxides (314), Finally, 1,2,5-benzoxathiazepines (315) have been prepared through a novel rearrangement of the unstable adducts of sulphene with A -benzylidene-2-hydroxyanilides. The compound obtained was identical with that produced unambiguously by an alternative route. 

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