Photoswitchable Regiodivergent Azidation of Olefins with Sulfonium Iodate(I) Reagent.

Photoswitchable strategy for selective azidation of structurally diverse olefins under transition-metal-free conditions is reported. The unprecedented reactivity of trimethylsulfonium [bis(azido)iodate(I)] species under visible light allows radical azidooxygenation of the C═C π bond with distinctive selectivity. In the absence of visible light, the reaction proceeds through an ionic intermediate which led to complementary regioselectivity to provide α-alkyl azides. Mechanistic studies reveal that light-controlled regiodivergent azidation involving radical or an ionic pathway can be accomplished with exclusive regioselectivity.

Chemoselective and stereospecific iodination of alkynes using sulfonium iodate(i) salt.

An efficient and highly chemoselective iodination of alkynes using a sulfonium iodate(i) electrophilc reagent under metal-free conditions has been realized. The reactivity of sulfonium iodate(i) salt could be significantly diverse in the presence of water as the solvent, enabling the (E)-1,2-diiodoalkenes stereospecifically. This stereodivergent approach is amenable to a wide range of alkyne substrates and demonstrates a diverse functional group tolerance resulting in synthetically valuable 1-iodoalkyne and (E)-vicinal-diiodoalkenes in good to excellent yields (up to 99%) with 100% selectivity under ambient conditions.

Regioselective vicinal functionalization of unactivated alkenes with sulfonium iodate(i) reagents under metal-free conditions.

Metal-free, molecular iodine-free direct 1,2-difunctionalization of unactivated alkenes has been reported. The sulfonium iodate(i) reagent efficiently promoted the intermolecular vicinal iodo-functionalization of a diverse range of olefins in a stereo and regioselective manner. This method enables the divergent and straightforward preparation of synthetically useful functionalities; ß-iodocarboxylates, ß-iodohydrins, and ß-iodoethers in a one-step process. Further interconversion of iodo-functionalized derivatives allows easy access to valuable synthetic intermediates en route to biologically active molecules.

Real-time perfusion echocardiography during treadmill exercise and dobutamine stress testing.

BACKGROUND: Real-time perfusion (RTP) echocardiographic imaging with a continuous infusion of microbubbles has improved the sensitivity of dobutamine stress echocardiography (DSE) in detecting coronary artery disease (CAD). The impact of RTP on treadmill exercise stress echocardiography (TESE) is unclear. Design Retrospective database review. SETTING/PATIENTS/INTERVENTIONS: RTP was utilised in 254 DSE and TESE patients being examined for the presence of significant CAD. A continuous infusion of 3% Definity (Lantheus Medical Imaging) was used for all studies, and contrast replenishment (MCR), plateau intensity (PMCE) and wall motion (WM) were examined for the detection of CAD. MAIN OUTCOME MEASURES: Sensitivity/specificity/accuracy to detect CAD. RESULTS: For DSE, the sensitivity of myocardial perfusion (MP) imaging with RTP was 85%, which was significantly higher than WM analysis (72%; p<0.05). The improvement in sensitivity with MP analysis during DSE was primarily the result of better detection of left anterior descending disease. MP sensitivity during TESE was significantly better than MP sensitivity during DSE (98% versus 85%; p<0.05), and WM sensitivity during TESE was better than WM sensitivity during DSE (89% versus 72%; p<0.05). The improvement in WM sensitivity during TESE was due to detection of subendocardial wall thickening abnormalities in 48% of the patients with induced subendocardial perfusion defects. CONCLUSION: Myocardial perfusion imaging with RTP improves the detection of CAD during both DSE and TESE. During TESE, the subendocardial perfusion defects improve WM sensitivity by delineating subendocardial WM abnormalities.