Stereoselective Oxidative Cyclization of <i>N</i> -Allyl Benzamides to Oxaz(ol)ines
Ayham H. Abazid, Tom-Niklas Hollwedel, Boris J. Nachtsheim
Abstract
This study presents an enantioselective oxidative cyclization of N-allyl carboxamides via a chiral triazole-substituted iodoarene catalyst. The method allows the synthesis of highly enantioenriched oxazolines and oxazines, with yields of up to 94% and enantioselectivities of up to 98% ee. Quaternary stereocenters can be constructed and, besides N-allyl amides, the corresponding thioamides and imideamides are well tolerated as substrates, giving rise to a plethora of chiral 5-membered N-heterocycles. By applying a multitude of further functionalizations, we finally demonstrate the high value of the observed chiral heterocycles as strategic intermediates for the synthesis of other enantioenriched target structures.