132283-38-6Relevant articles and documents
Rhodium-catalysed Reaction of Methyl Diazoacetoacetate with 5-(p-Methoxyphenyl)-1,3,4-oxathiazol-2-one; Isolation and Crystal Structure of Methyl 2-(p-Methoxyphenyl)-6-methyl-1,4,3-oxathiazine-5-carboxylate
Blake, Alexander J.,Brownsort, Peter A.,Gosney, Ian,Paton, R. Michael
, p. 2656 - 2668 (2007/10/02)
The rhodium(II)-catalysed reaction of methyl diazoacetoacetate with 5-(p-methoxyphenyl)-1,3,4-oxathiazol-2-one afforded p-methoxybenzonitrile, the title 1,4,3-oxathiazine (17), dithietane (9), and thiirane (10).The structure of the oxathiazine was confirmed by X-ray crystallography; the heterocyclic ring is folded (20 deg) along the S-O axis.A mechanism is proposed involving initial formation of a sulphonium ylide (23) followed by ring expansion with decarboxylation.The oxathiazine is thermally unstable undergoing retro-Diels Alder fragmentation to p-methoxybenzonitrile and dithietane and thiirane products derived from methyl α-thioxoacetoacetate.The corresponding reaction with dimethyl diazomalonate afforded p-methoxybenzonitrile and oligomers of dimethyl α-thioxomalonate; an intermediate oxathiazine was not detected.