Lewis acid-mediated Suzuki–Miyaura Cross-Coupling Reaction

The palladium-catalysed Suzuki–Miyaura cross-coupling (SMC) reaction of organohalides and organoborons is a reliable method for carbon–carbon bond formation. This reaction involves a base-mediated transmetalation process, but the presence of a base also promotes competitive protodeborylation, which reduces the efficiency. Herein, we established an SMC reaction via Lewis acid-mediated transmetalation of an organopalladium(II) intermediate with organoborons. Experimental and theoretical investigations indicate that the controlled release of the transmetalation-active intermediate enabled base-independent transmetalation under heating conditions and enhanced the applicable scope of this process. This system enabled us to avoid the addition of a base, and thus, rendered substrates with base-sensitive moieties available. Results from this research further expand the overall utility of cross-coupling chemistry

MRCP imaging at 3.0 T vs. 1.5 T: Preliminary experience in healthy volunteers.

PURPOSE: To evaluate the impact of magnetic resonance cholangiopancreatography (MRCP) imaging at 1.5T and 3.0T on image quality. MATERIALS AND METHODS: Fourteen volunteers were examined at both 1.5T and 3.0T using MRCP imaging performed with a breath-held two-dimensional (2D) half-Fourier acquired single-shot turbo spin-echo (HASTE) thick-slab sequence, a free-breathing navigator-triggered three-dimensional (3D) turbo spin-echo (TSE) sequence with prospective acquisition correction, and a heavily T2-weighted (T2W) sequence with breath-held multislice HASTE. All images were scored for visualization of the biliary and pancreatic ducts, severity of artifacts, image noise, and overall image quality. RESULTS: MRCP imaging at 3.0T yielded a significant improvement in overall image quality compared to 1.5T. We found a trend for superior visualization of the biliary and pancreatic ducts at 3.0T. Heavily T2W imaging with thin sections (1.4 mm) at 3.0T provided diagnostic images and better visualization of the biliary and pancreatic ducts than heavily T2W imaging with standard sections (2.8 mm) at 3.0T. CONCLUSION: Our experience suggests that MRCP imaging at 3.0T has the potential to provide excellent images. High-resolution heavily T2W imaging with a small voxel size (1.3 x 1.3 x 1.4 mm) at 3.0T can provide diagnostic images and allow evaluation of small pathologies of the bile and pancreatic ducts, which 1.5T MRI cannot sufficiently visualize