 Oxaziridines have been found to undergo rearrangement reactions via a radical mechanism when irradiated with UV light or in the presence of a single electron transfer reagent such as CuI. spirocylic oxaziridines undergo ring expansions to the corresponding lactam . Interestingly , the migrating substituent is determined by a stereoelectronic effect where the group trans to the lone pair on the nitrogen will always be the predominant migration product . In light of this effect , it is possible to take advantage of the chiral nitrogen due to high inversion barrier to direct the rearrangement . This phenomenon is demonstrated by observed selectivities in the rearrangements below . In the rearrangement on the left the thermodynamically unfavorable product is observed exclusively , while in the reaction on the right the product derived from the less stable radical intermediate is favored . 
 Oxaziridines <a href='been_done' title='1'><mark>have</mark></a> been found to undergo rearrangement reactions via a radical mechanism when irradiated with UV light or in the presence of a single electron transfer reagent such as CuI. spirocylic oxaziridines undergo ring expansions to the corresponding lactam . Interestingly , the migrating substituent is determined by a stereoelectronic effect where the group trans to the lone pair on the nitrogen will always be the predominant migration product . In light of this effect , it <a href='drop_aux' title='2'><mark>is</mark></a>possible to take advantage of the chiral nitrogen due to high inversion barrier to direct the rearrangement . This phenomenon is demonstrated by observed selectivities in the rearrangements below . In the rearrangement on the left the thermodynamically unfavorable product is observed exclusively , while in the reaction on the right the product derived from the less stable radical intermediate is favored . 
Oxaziridines done been found to undergo rearrangement reactions via a radical mechanism when irradiated wid UV light or in the presence of a single electron transfer reagent such as CuI. spirocylic oxaziridines undergo ring expansions to da corresponding lactam . Interestingly , the migrating substituent is determined by a stereoelectronic effect where the group trans to tdalone pair on the nitrogen will always b the predominant migration product . In light of dis effect , it possible to take advantage of thdahiral nitrogen due to high inversion barrier to direct thedaarrangement . This phenomenon is demonstrated by observed selectivities in the darrangements below . In the rearrangement on the left the thermodynamically unfavorable product is observed exclusively , while in the reaction on the rda the product derived from the ledastable radical intermediate is favored .