Organic isocyanates are versatile intermediates that provide access to a wide range of functionalities. In this work, we have developed the first synthetic method for preparing aliphatic isocyanates via direct C-H activation. This method proceeds efficiently at room temperature and can be applied to functionalize secondary, tertiary, and benzylic C-H bonds with good yields and functional group compatibility. Moreover, the isocyanate products can be readily converted to substituted ureas without isolation, demonstrating the synthetic potential of the method. To study the reaction mechanism, we have synthesized and characterized a rare Mn-NCO intermediate and demonstrated its ability to transfer the isocyanate moiety to alkyl radicals. Using EPR spectroscopy, we have directly observed a Mn intermediate under catalytic conditions. Isocyanation of celestolide with a chiral manganese salen catalyst followed by trapping with aniline afforded the urea product in 51% enantiomeric excess. This represents the only example of an asymmetric synthesis of an organic urea via C-H activation. When combined with our DFT calculations, these results clearly demonstrate that the C-NCO bond was formed through capture of a substrate radical by a Mn-NCO intermediate.

Mixtures of chloride and iodate salts for light alkane oxidation achieve >20% yield of methyl trifluoroacetate (TFA) from methane with >85% selectivity. The mechanism of this C−H oxygenation has been probed by examining adamantane as a model substrate. These recent results lend support to the involvement of free radicals. Comparative studies between radical chlorination and iodate/chloride functionalization of adamantane afford statistically identical 3°:2°selectivities (∼5.2:1) and kinetic isotope effects for C−H/C−D functionalization (k H /k D = 1.6(3), 1.52(3)). Alkane functionalization by iodate/chloride in HTFA is proposed to occur through H-atom abstraction by free radical species including Cl • to give alkyl radicals. Iodine, which forms by in situ reduction of iodate, traps alkyl radicals as alkyl iodides that are subsequently converted to alkyl esters in HTFA solvent. Importantly, the alkyl ester products (RTFA) are quite stable to further oxidation under the oxidizing conditions due to the protecting nature of the ester moiety.

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» The use of preoperative antibiotic prophylaxis is not supported for elective cases of patients undergoing soft-tissue hand procedures that are ≤2 hours in length. » The use of preoperative antibiotic prophylaxis is not supported for patients with diabetes undergoing elective, soft-tissue hand surgical procedures. » There is a paucity of literature evaluating the use of preoperative antibiotic prophylaxis in patients with rheumatoid arthritis, those with cardiac valves, and those taking corticosteroids; because of this, there is no evidence to vary from our general recommendations. Surgical site infections are a major source of morbidity and impose a large economic burden in orthopaedic surgery 1-3. Preoperative antibiotic prophylaxis is commonly used to prevent surgical site infection. Although there is evidentiary support for the use of preoperative antibiotic prophylaxis for many orthopaedic procedures (e.g., open fractures 4-6 , lowerextremity fractures 7-9 , and total joint replacement 10-12), the use of preoperative antibiotic prophylaxis for elective soft-tissue hand surgical procedures is controversial 13,14. For example, current recommendations from the American Association of Plastic Surgeons are to not utilize preoperative antibiotic prophylaxis for clean hand surgical procedures, and current recommendations from the American Academy of Orthopaedic Surgeons are to not utilize preoperative antibiotic prophylaxis for carpal tunnel release 15,16. Despite these recommendations, 2 surveys of hand surgeons reported rates of antibiotic use for carpal tunnel syndrome between 31% and 49% 17,18. Although millions of soft-tissue hand procedures are performed each year 19,20 , the rate of infection is reported to be low, with studies showing infection rates between 0.3% and 1.5% 13,21-25 for elective cases (e.g., carpal tunnel release and trigger finger release). Although the rate of infection for urgent soft-tissue cases is reported to be higher (e.g., 1.1% to 9.8% for lacerations, open fractures, or bite injuries 26-28), this review will focus on elective soft-tissue surgical procedures (e.g., carpal tunnel release, trigger finger release, Dupuytren contracture release). Despite the low rate of infections, complications can be devastating, leading to soft-tissue loss, stiffness, scarring, and amputation 29. Preoperative antibiotic prophylaxis, given to prevent infection, is associated with its own complications,