Abstract A productive approach has been developed to spirocyclopropane-annelated 1, 4- benzoxathiane 17 (85%), 1, 4-benzothiazines 20− 22 (56− 88%) and 1, 4-benzoxazines 25, 26 (55− 71%), through Michael additions of binucleophilic o-hydroxythiophenol 15, o- aminothiophenols 8 and o-hydroxysulfanilides 23 onto methyl and tert-butyl 2-chloro-2- cyclopropylideneacetates (1-Me, 1-tBu), followed by ring closure in the intermediate of ...
