text:  Additionally , oxidation of chiral <unk> and oxidation of <unk> with chiral <unk> may yield <unk> <unk> . Some <unk> have the unique property of <unk> stable nitrogen atoms at room temperature due to an inversion barrier of 24 to 31 kcal / mol . <unk> <unk> where stereochemistry is entirely due to <unk> stable nitrogen are reported . 
  