Upon reaction with PhI(OAc)(2), α-oxo-aldoximes are oxidized to α-oxo-nitrile oxides, while α-oxo-ketoximes are converted into nitrile oxides via the oxidative cleavage of the carbonyl-imino σ bond. The nitrile oxides thus formed were trapped with norbornene or styrene in good yield. α,α'-Dioxo-ketoximes react less efficiently.

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Purpose Novel devices such as the barrier enclosure were developed in hopes of improving provider safety by limiting SARS-CoV-2 transmission during tracheal intubation. Nevertheless, concerns arose regarding a lack of rigorous efficacy and safety data for these devices. We conducted a randomized controlled trial to evaluate the impact of the barrier enclosure on time to tracheal intubation. Method After Research Ethics Board approval, elective surgical patients with normal airway predictors were randomly allocated 1:1 to tracheal intubation with or without a barrier enclosure. The primary outcome was time to tracheal intubation. Secondary outcomes included first-pass success rate, total time of airway manipulation, anesthesiologists’ perception of intubation difficulty, likelihood of use in SARS-CoV-2-positive patients, and patients’ perception of comfort and acceptability. Results There were 48 participants in the barrier enclosure group and 46 participants in the control group. The mean (standard deviation [SD]) time to tracheal intubation was 62 (29) sec with barrier closure and 53 (27) sec without barrier enclosure (mean difference, 9 sec; 95% confidence interval, − 3 to 20; P = 0.14). Anesthesiologists rated the difficulty of intubation higher with barrier enclosure (mean [SD] visual analogue scale score, 27 [26] mm vs 9 [17] mm; P < 0.001). There were no significant differences in other secondary outcomes. Conclusion In healthy surgical patients with normal airway predictors, the use of a barrier enclosure during tracheal intubation did not significantly prolong time to intubation or decrease first-pass intubation success. Nevertheless, there was an increase in difficulty of intubation perceived by the anesthesiologists with use of a barrier enclosure. Trial registration www.clinicaltrials.gov (NCT04366141); registered 28 April 2020. Supplementary Information The online version contains supplementary material available at 10.1007/s12630-021-02024-z.