Asymmetric synthesis of fortucine and reassignment of its absolute configuration.

A convergent and enantioselective synthesis of fortucine was achieved from the starting materials tyrosine methyl ester and 3-hydroxy-4-methoxybenzaldehyde. The synthesis is based on two key steps mediated by a hypervalent iodine reagent. This work has enabled us to reassign the absolute configuration of the natural product reported in the literature.

Oxidative 1,2- and 1,3-alkyl shift processes: developments and applications in synthesis.

Oxidative 1,2- and 1,3- alkyl shifts mediated by a hypervalent iodine reagent were performed on simple and inexpensive phenol derivatives. These transpositions enable rapid redesign of the main aromatic skeleton to generate good yields of highly functionalized scaffolds containing a prochiral dienone system, a quaternary carbon center connected to as many as four sp(2) centers, and a carbonyl functionality or precursor. An efficient enantioselective version of this process resulting in the formation of a challenging quaternary carbon center is also described. The products represent the central cores of several natural products having important bioactivities. As an illustration of the potential of this method, we describe the rapid synthesis of several functionalized polycyclic systems as well as a formal synthesis of acetylaspidoalbidine, a hexacyclic alkaloid belonging to the Aspidosperma family.

Oxidative Prins-pinacol tandem process mediated by a hypervalent iodine reagent: scope, limitations, and applications.

An oxidative Prins-pinacol tandem process mediated by a hypervalent iodine reagent has been developed. This oxidative version of the famous tandem process fits within the concept of "aromatic ring umpolung" and allows the stereoselective transformation of simple phenols into highly elaborated spirocyclic dienone cores containing several quaternary carbon centers. The scope and the limitations of this process, including the study of its stereoselectivity, are described in this article. As a direct application of this stereoselective process, we describe the formal synthesis of (-)-platensimycin, an important antibiotic agent.

Evaluation of auditory functions for Royal Canadian Mounted Police officers.

BACKGROUND: Auditory fitness for duty (AFFD) testing is an important element in an assessment of workers' ability to perform job tasks safely and effectively. Functional hearing is particularly critical to job performance in law enforcement. Most often, assessment is based on pure-tone detection thresholds; however, its validity can be questioned and challenged in court. In an attempt to move beyond the pure-tone audiogram, some organizations like the Royal Canadian Mounted Police (RCMP) are incorporating additional testing to supplement audiometric data in their AFFD protocols, such as measurements of speech recognition in quiet and/or in noise, and sound localization. PURPOSE: This article reports on the assessment of RCMP officers wearing hearing aids in speech recognition and sound localization tasks. The purpose was to quantify individual performance in different domains of hearing identified as necessary components of fitness for duty, and to document the type of hearing aids prescribed in the field and their benefit for functional hearing. The data are to help RCMP in making more informed decisions regarding AFFD in officers wearing hearing aids. RESEARCH DESIGN: The proposed new AFFD protocol included unaided and aided measures of speech recognition in quiet and in noise using the Hearing in Noise Test (HINT) and sound localization in the left/right (L/R) and front/back (F/B) horizontal planes. Sixty-four officers were identified and selected by the RCMP to take part in this study on the basis of hearing thresholds exceeding current audiometrically based criteria. This article reports the results of 57 officers wearing hearing aids. RESULTS: Based on individual results, 49% of officers were reclassified from nonoperational status to operational with limitations on fine hearing duties, given their unaided and/or aided performance. Group data revealed that hearing aids (1) improved speech recognition thresholds on the HINT, the effects being most prominent in Quiet and in conditions of spatial separation between target and noise (Noise Right and Noise Left) and least considerable in Noise Front; (2) neither significantly improved nor impeded L/R localization; and (3) substantially increased F/B errors in localization in a number of cases. Additional analyses also pointed to the poor ability of threshold data to predict functional abilities for speech in noise (r² = 0.26 to 0.33) and sound localization (r² = 0.03 to 0.28). Only speech in quiet (r² = 0.68 to 0.85) is predicted adequately from threshold data. CONCLUSIONS: Combined with previous findings, results indicate that the use of hearing aids can considerably affect F/B localization abilities in a number of individuals. Moreover, speech understanding in noise and sound localization abilities were poorly predicted from pure-tone thresholds, demonstrating the need to specifically test these abilities, both unaided and aided, when assessing AFFD. Finally, further work is needed to develop empirically based hearing criteria for the RCMP and identify best practices in hearing aid fittings for optimal functional hearing abilities.

An unprecedented oxidative Wagner-Meerwein transposition.

An oxidative Wagner-Meerwein transposition involving different functionalities mediated by a hypervalent iodine reagent has been accomplished. The strategy fits within the concept of "aromatic ring umpolung" and allows rapid access to highly functionalized cores.

Cerebral arterial gas embolism following diagnostic bronchoscopy: delayed treatment with hyperbaric oxygen.

PURPOSE: To describe a clinical scenario consistent with the diagnosis of cerebral arterial gas embolism (CAGE) acquired during an outpatient bronchoscopy. Our discussion explores the mechanisms and diagnosis of CAGE and the role of hyperbaric oxygen therapy. CLINICAL FEATURES: A diagnostic bronchoscopy was performed on a 70-yr-old man who had had a lobectomy for bronchogenic carcinoma three months earlier. During the direct insufflation of oxygen into the right middle lobe bronchus, the patient became unresponsive and developed subcutaneous emphysema. Immediately, an endotracheal tube and bilateral chest tubes were placed with resultant improvement in his oxygen saturation. However, he remained unresponsive with extensor and flexor responses to pain. Later, in the intensive care unit, he exhibited seizure activity requiring anticonvulsant therapy. Sedation was utilized only briefly to facilitate controlled ventilation. Investigations revealed a negative computerized tomography (CT) scan of the head, a normal cerebral spinal fluid examination, a CT chest that showed evidence of barotrauma, and an abnormal electroencephalogram. Fifty-two hours after the event, he was treated for presumed CAGE with hyperbaric oxygen using a modified United States Navy Table 6. Twelve hours later he had regained consciousness and was extubated. He underwent two more hyperbaric treatments and was discharged from hospital one week after the event, fully recovered. CONCLUSION: A patient with presumed CAGE made a complete recovery following treatment with hyperbaric oxygen therapy even though it was initiated after a significant time delay.