A nickel(II) catalyzed enantioselective thio-Claisen rearrangement of α-diazo pyrazoleamides with thioindoles was realized with modified chiral N,N′-dioxide ligands, affording a variety of C3-substituted indole derivatives in high yields (up to 95%) with excellent enantioselectivities (up to 96% ee) undermild reaction conditions. A possible transition state model was proposed based on previous reports
A Rigid Molecular Balance for Measuring Face-to-Face Arene−Arene Interactions
作者:William R. Carroll、Perry Pellechia、Ken D. Shimizu
DOI:10.1021/ol801286k
日期:2008.8.21
A new molecular balance was developed to measure face-to-face arene-arene interactions. The balance adopts distinct folded and unfolded conformations due to restricted rotation about a C-aryl-N-imide bond. In the folded conformer, the rigid bicyclic framework enforces an offset face-to-face geometry to the exclusion of edge-to-face geometries, which was verified by X-ray crystallography. Measurement of the folded to unfolded ratio yields accurate values for the arene-arene interaction in a range of different solvents.