Heteroannulation of Arynes with α-Bromodifluorohydroxamates: An Efficient and General Approach to Access 2,2-Difluoro Indoxyls.

Herein, we report the first general approach to access N -alkoxy-2,2-difluoro indoxyls, via formal 3 + 2 cycloaddition of aryne and (putative) fluorinated-aza-oxyallyl cation. This transition-metal/oxidant-free transformation occurs under mild reaction conditions with a short reaction time. Mechanistic investigation indicates the possible involvement of the closed form of fluorinated-aza-oxyallyl cation, viz., α-lactam, in the current transformation.