(3 R ,7 a S )‐3‐(Trichloromethyl)Tetrahydropyrrolo[1,2‐ C ]Oxazol‐1(3 H )‐One: An Air and Moisture Stable Reagent for the Synthesis of Optically Active α‐Branched Prolines

Abstract ( S )‐Proline 2,2,2‐Trichloro‐1‐ethoxyethanol (3 R ,7 aS )‐3‐(Trichloromethyl)tetrahydropyrrolo[1,2‐ c ]oxazol‐1(3 H )‐one Sodium Acetyl chloride ( R )‐Methyl 2‐allylpyrrolidine‐2‐carboxylate hydrochloride