We have developed a low temperature magnetic force microscope capable of operation down to 6 K in vacuum by using piezoresistive cantilevers. We use the non-contact frequency modulation technique to detect the magnetic force gradient between an iron-coated tip and the sample. We demonstrate the operation of this new instrument by obtaining images of magnetic domains in VHS tape at room temperature, 77 and 6 K. This microscope is ideally suited for the characterization of thin films of high temperature superconductors.

A formal [5 + 3] cycloaddition of zwitterionic allylpalladium intermediates with 1,3-dipoles is developed, providing N,O-containing eight-membered heterocyclic compounds in high yields. Catalytically generated zwitterionic allylpalladium intermediates in situ from vinylethylene carbonates or vinyloxiranes acted as dipolarophile.

With the use of a commercially available chiral phosphine as the catalyst, the first catalytic enantioselective [4 + 3] annulation of allenoates with C,N-cyclic azomethine imines is developed. The reaction works efficiently under mild reaction conditions to afford seven-membered ring-fused quinazoline-based tricyclic heterocycles in high yields with good to excellent diastereo- and enantioselectivities.

The first phosphine-catalyzed [5+1] annulation of enones with N-sulfonylimines works efficiently to give tetrahydropyridines.

The nine-membered ring-bearing bicyclo[5.2.2]­tetrahydrooxonines frameworks have enantioselectively been constructed via a tandem [3 + 2] cycloaddition/Cope rearrangement reaction of vinylethylene carbonates (VECs) with coumalates or pyrones. Under mild conditions, palladium-catalyzed asymmetric tandem reaction of various substituted VECs and coumalates or pyrones proceeds smoothly to produce the corresponding medium-sized heterocyclic compounds in high yields with very high enantioselectivities. Moreover, the reaction on the gram scale and further diverse transformations of the products were workable. The reaction mechanism was investigated through control experiments and DFT calculations, which show the reaction proceeds via a tandem [3 + 2] cycloaddition/Cope rearrangement pathway rather than via a [5 + 4] cycloaddition pathway.