Stereoselective Oxidative Cyclization of N-Allyl Benzamides to Oxaz(ol)ines

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.

Automated summary

This study introduces an enantioselective oxidative cyclization method for N-allyl carboxamides using a chiral triazole-substituted iodoarene catalyst, yielding highly enantioenriched oxazolines and oxazines with up to 94% yield and 98% ee enantioselectivity. The method is versatile, allowing the construction of quaternary stereocenters and the use of various substrates beyond N-allyl amides, demonstrating the value of the chiral heterocycles as strategic intermediates for the synthesis of other enantioenriched target structures.