The first catalytic asymmetric cross-dehydrogenative coupling of cyclic carbamates and terminal alkynes has been established. The reaction features high enantiocontrol and excellent functional group tolerance and displays a wide range of structurally and electronically diverse carbamates as well as terminal alkynes. N-Acyl hemiaminals were identified as the reactive intermediates through preliminary control experiments. Employing readily removable carbamates as substrates rather than traditionally adopted N-aryl amines allows applications in complex molecule synthesis and therefore advances the C-H functionalization strategy to a synthetically useful level.
We investigated all-inside ankle arthroscopy for Tillaux-Chaput fractures. We retrospectively evaluated 19 patients (12 males [63.2%] and 7 [36.8%] females; 11 right [57.9%] and 8 left [42.1%] ankles) treated from May 2013 to January 2016. Their mean age was 28.1 (range 10 to 55) years. Sixteen (84.2%) had single Tillaux-Chaput fractures and 3 (15.8%) had combined proximal fibular fractures; 17 (89.5%) were diagnosed radiographically and 2 (10.5%) by computed tomography. Anterolateral and anteromedial ankle arthroscopy was used for closed reduction and internal fixation with 1 or 2 Herbert screws. Joint function was evaluated using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale. All 19 patients healed by first intention without nerve, vessel, or tendon injuries. The follow-up was 19.0 (range 12 to 25) months; fracture union was achieved by 23.5 (range 12 to 36) weeks. At the last follow-up, the 19 patients had no restrictions in ankle function and range of motion, with no ankle or walking pain. The AOFAS score changed from 52.8 to 91.7 points, with an excellent/good rate of 100%. These results suggest that anterolateral and anteromedial all-inside ankle arthroscopy is a precise and effective method for closed reduction and internal fixation of Tillaux-Chaput fractures.
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