The furan approach to thiacyclic compounds. Stereoselective synthesis of 2,3-disubstituted tetrahydrothiopyrans

We describe an efficient new approach to the synthesis of thiacyclic compounds that extends the methodology we previously developed for oxacycles: oxidation of a furan ring with singlet oxygen, followed by intramolecular hetero Michael addition. The new approach provides a new entry to nucleoside analogues and α-glucosidase inhibitors.     

Transfer of angular momentum to matter from acoustical vortices in free space

An experimental demonstration of the mechanical transfer of orbital angular momentum to matter from acoustical vortices in free field is presented. Vortices with topological charges l=+/-1 and l=+/-2 were generated and a torsion pendulum was used to study the angular momentum transfer to hanging disks of several sizes. This allowed us to make a comparative study of the effective acoustical torque in terms of topological charge of the vortex, the disk radius, and its position along the main propagation axis. A theoretical discussion of the generated sound fields is also provided.