The doping effect of fluorinated aromatic hydrocarbon solvents on the performance of common olefin metathesis catalysts: application in the preparation of biologically active compounds.

Aromatic fluorinated hydrocarbons, used as solvents for olefin metathesis reactions, catalysed by standard commercially available Ru precatalysts, allow substantially higher yields to be obtained, especially of challenging substrates, including natural and biologically active compounds.

The smiles rearrangement and the julia-kocienski olefination reaction.

Molecular rearrangements consisting of base- or acid-induced dislocation of aromatic or heteroaromaticrings are reviewed. The emphasis is given to recent developments and, in particular, to synthetic applicationof the rearrangement. A novel classification has been applied in order to discuss systematically ratherdiverse published data. The rearrangements are reviewed according to atoms entering and leaving the ipso-position of the migrating ring. The Julia-Kocienski olefination reactionis presented in other parts of this volume.

Olefination of alpha-hydroxy or alpha-aminoaldehyde derivatives via reaction of their arylsulfonylhydrazones with sulfonyl anions.

Reaction of tosylhydrazones of O-substituted alpha-hydroxy or N-substituted alpha-amino aldehydes (2, 7, 11, 15, 17, and 20) with selected alpha-magnesio alkyl phenyl sulfones afforded the respective derivatives of allylic alcohols or allylic amines. 2,3-O-Isopropylidene-D-glyceraldehyde (1) was transformed into its tosylhydrazone (2) and then olefins 4a with retention of optical purity.