Tsutomu Katsuki

Three‐ and seven‐membered rings were constructed by the title reaction of terminal olefins with vinyldiazolactone as a carbene source, the seven‐membered rings upon subsequent hydrolysis and Cope rearrangement when 1,3‐dienes were used (see example). The α‐spirocyclopropyl lactones were formed with high E (trans) selectivity and high enantioselectivity, and cyclopropanation occurred at the terminal double bond in 1,3‐dienes with excellent regioselectivity. magnified image

The aluminium(salalen) complex was found to be an efficient catalyst for the asymmetric oxidation of sulfides under solvent-free or highly concentrated conditions, in which an only 0.002–0.01 mol% catalyst loading was sufficient to obtain optically active sulfoxides in high yield with high enantioselectivity.

Asymmetric oxidation catalysis with an aluminum‐based complex was achieved by a combination of newly synthesized chiral aluminum(salalen) complexes (salalen=half‐reduced salen=salan/salen‐hybridized [ONNO]‐type tetradentate ligand; salan=reduced salen, salen=N,N′‐ethylenebis(salicylideneiminato)) derived from binol (1,1′‐bi‐2,2′‐naphthol) with aqueous hydrogen peroxide as the oxidant. The combination was found to be efficient for asymmetric sulfur oxidation. Various sulfides were smoothly converted into the corresponding sulfoxides with high to excellent enantioselectivity. Thioacetals are also good substrates for the oxidation.