One-Pot Synthesis of N -Hydroxypyrroles via Soft α-Vinyl Enolization of ( E )-β-Chlorovinyl Ketones: A Traceless Arylsulfinate Mediator Strategy.

A traceless arylsulfinate mediator strategy has been developed to switch the reaction course of β-chlorovinyl ketones with N -hydroxyamine. The soft α-vinyl enolization of ( E )-β-chlorovinyl ketones was conducted in the presence of sodium arylsulfinate to give transient alkenyl sulfones that in turn reacted with NH 2 OH to give novel access to N -hydroxypyrroles. The mechanistic studies revealed the initial formation of oxazine intermediates that rearranged to thermodynamically stable aromatic products, N -hydroxypyrroles, under microwave-assisted heating conditions.