Copper-Mediated [3+2] Annulation of 3-N-Hydroxyallylamines with Nitrosoarenes

Abstract

Cu-mediated annulations of N-hydroxyallylamines with nitrosoarenes proceed through unprecedented formal [3+2] cycloadditions of N-hydroxyaminoallyl radicals with nitrosoarenes. Our mechanistic analysis opposes a 5-endo-trig cyclization involved in the final ring-closure step. To manifest the reaction utility, chemical elaborations of resulting isoxazolidinyl products into 2- or 3-substituted quinoline N-oxides and acyclic 1,3-diamino-2-ols are also described.

Keywords: annulation; copper; nitrosoarenes; oxidants; radicals.