The late-stage oxidation of substituted pyrrolidines offers good flexibility for the construction of γ-lactam libraries, and especially in recent years the methods for functionalization of pyrrolidine have been available. We reported a new strategy for oxidation of pyrrolidines to γ-lactams: reaction of pyrrolidine with an o-benzoquinone gives an N,O-acetal by direct oxidation of the α-C-H bond of the pyrrolidine ring, and then the N,O-acetal is further oxidized by the o-benzoquinone to the γ-lactam. Because the first oxidation occurs selectively at the α-C-H of the pyrrolidine ring, oxidation-sensitive functional groups (allyl-, vinyl-, hydroxyl-, and amino groups) on pyrrolidine ring are unaffected. The synthetic utility of this novel method was demonstrated by the facile syntheses of (S)-vigabatrin and two analogues.

Rationale: Massive mediastinal tumors present a major challenge for surgery and anesthesia management due to possible perioperative circulation and respiratory dysfunction. Patient concerns: A 36-year-old female underwent difficulty with tracheal extubation and required mechanical ventilation for 3 months after resection of a massive mediastinal tumor. Diagnoses: Postoperative B-ultrasound examination of diaphragmatic motor weakness and electrophysiological examination indicated respiratory failure due to phrenic nerve injury. Interventions: The patient failed tracheal extubation several times after the operation and finally a tracheotomy was performed. Mechanical ventilation, anti-infective treatment, and systemic supportive treatment were provided. Outcomes: The patient recovered well after tracheotomy and approximately 3 months of ventilation support. Lessons: Weaning difficulty caused by phrenic nerve injury seriously affected patient postoperative rehabilitation. To reduce the occurrence of similar problems, intraoperative phrenic nerve electrophysiological monitoring should be conducted.