CuCl/AgSbF6 and Rh2(OAc)4 Comparison for the Synthesis of N-O Tethered Three and Five Membered Rings via Diazo Chemistry

Diazocarbonyl compounds are versatile precursors of carbenes leading to various structures by using several metal catalysts, especially copper and rhodium salts. In this study, eight different diazocarbonyls having N-O moiety were used. The N-O tethered structures were preferred because they may allow some useful transformations of the final products into valuable compounds via N-O cleavage. In the presence of a double bond on the –OR function of the starting diazo compound, CuCl/AgSbF6 catalyst yielded only cyclopropyl fused oxazinane/oxazepane derivatives over cyclopropanation while Rh2(OAc)4 catalyst was giving mainly isooxazolidinones via C-H insertion.