A Rare Case of Stroke in an Adolescent Violinist Due to Thoracic Outlet Syndrome.

Thoracic outlet syndrome (TOS), a rare condition, results from the compression of neurovascular structures traversing from the neck through the thoracic outlet into the axilla. It can develop from chronic repetitive activities of the upper extremities, commonly reported in athletes playing sports involving vigorous use of arms and shoulders. While symptoms of neurovascular compression can occur, stroke due to TOS in children is not commonly reported. We describe a rare case of a healthy 14-year-old boy, a competitive violinist, with acute limb ischemia from extensive occlusive thrombi involving several arteries in the right upper extremity as well as the right vertebral artery, which ultimately caused infarcts in the bilateral posterior circulation. The etiology was determined to be TOS leading to impingement of the right subclavian artery by a fused cervical rib aggravated by patient's prolonged violin practice. This case represents the first description of stroke from TOS in an adolescent violinist.

Coupling of Vinyl Aziridines and Isocyanates.

Thermal coupling of vinyl aziridines and phenyl isocyanate was evaluated. Although oxazolidinone products were predominant, some reactions afforded a seven-membered ring heterocycle. When Ni/IMes was employed as a catalyst, a wider array of vinyl aziridines underwent coupling reactions. The Ni catalyzed reactions generally afforded vinyl imidazolidinones as major products.

Reduction of beta-hydroxyketones by SmI2/H2O/Et3N.

Reduction of a series of beta-hydroxyketones by SmI2/H2O/Et3N provided 1,3-diols in quantitative yields. The reactions were exceedingly clean with no byproduct formation, negating the need for further purification. Most reactions provided moderate to excellent diastereoselectivity with syn-diols as the major isomer in most instances.

Solvent-dependent diastereoselectivities in reductions of beta-hydroxyketones by SmI2.

The reductions of a series of beta-hydroxyketones by SmI(2) were examined in THF, DME, and CH(3)CN using methanol as a proton source. Reductions in THF and DME typically lead to the syn diastereomer with DME providing higher diastereoselectivities. Reductions in CH(3)CN provided the anti diastereomer predominantly. This study reveals that solvation plays an important role in substrate reduction by SmI(2). [reaction: see text]

The role of proton donors in SmI2-mediated ketone reduction: new mechanistic insights.

The effects of proton donors (alcohols and water) on the rate of reduction of acetophenone by SmI2 have been examined utilizing stopped-flow spectrophotometric studies. The rate orders with respect to proton source and the kinetic isotope effects were determined as well. The reaction was first-order in phenol, 2,2,2-trifluoroethanol, methanol, and ethanol and zero-order in 2-propanol and 2-methyl-2-propanol when 25 equiv of proton source were used in the reduction. Methanol, ethanol, 2,2,2-trifluoroethanol, and phenol also showed a direct correlation between the pKa of the alcohol and the rate of reduction. Under the same conditions, water had a fractional rate order of 1.4. Further studies showed that water has a rate order of 1 at lower concentrations (<8 equiv) and a rate order of 2 at higher concentrations (>80 equiv). These results clearly indicate that the nature of the proton donor and its concentration affects the rates of reduction. Water has a high affinity for SmI2 (compared to that of the alcohols), and the onset of coordination at relatively low concentrations channels the reaction through a mechanistically distinct pathway.