Unusual selectivity in the ring-opening of γ-valerolactone oxide by amines.

Primary and secondary amines selectively react with the lactone moiety of γ-valerolactone oxide (GVLO). Several primary amines afforded the resulting epoxyamides with an intact epoxy group. In some cases addition of two equivalents of amine resulted in additional epoxide opening to give α,γ-dihydroxy-ß-amino-amides. The selective lactone-opening in GVLO was further corroborated by DFT-studies.

New bifunctional monomers from methyl vinyl glycolate.

Methyl vinyl glycolate (MVG) can be obtained by acid-catalyzed conversion of C4 and C6 sugars. Applications of MVG in polymers are so far limited to its use as co-monomer for poly(lactic acid) and as crosslinking agent. In this work, hydroformylation and methoxycarbonylation of MVG were investigated to produce novel bifunctional monomers. Polyesters with high renewable-atom content were successfully prepared and characterized.

Copper-Catalyzed Carbonylative Hydroamidation of Styrenes to Branched Amides.

Amides are one of the most ubiquitous functional groups in synthetic and medicinal chemistry. Novel and rapid synthesis of amides remains in high demand. In this communication, a general and efficient procedure for branch-selective hydroamidation of vinylarenes with hydroxyamine derivatives enabled by copper catalysis has been developed for the first time. The reaction proceeds under mild conditions and tolerates a broad range of functional groups. Applying a chiral phosphine ligand, an enantioselective variant of this transformation was achieved, affording a variety of chiral α-amides with excellent enantioselectivities (up to 99 % ee) and high yields.

Copper-Catalyzed Regioselective Borocarbonylative Coupling of Unactivated Alkenes with Alkyl Halides: Synthesis of ß-Boryl Ketones.

The borocarbonylative coupling of unactivated alkenes with alkyl halides remains a challenge. In this communication, a Cu-catalyzed borocarbonylative coupling of unactivated alkenes with alkyl halides for the synthesis of ß-boryl ketones has been developed. A broad range of ß-boryl ketone derivatives was prepared in moderate to excellent yields with complete regioselectivity.

A general benzylic C-H activation and C-C coupling reaction of zirconocenes mediated by C-N bond cleavage in tert-butylisocyanide - unusual formation of iminoacyl complexes.

Reactions of the zirconocene alkyne complex [rac-(ebthi)Zr(η2-Me3SiC2SiMe3)] (rac-(ebthi) = rac-1,2-ethylene-1,1'-bis(η5-tetrahydroindenyl)) with tert-butylisocyanide and methylbenzenes were investigated. Depending on the stoichiometry, the solvent and the reaction temperature different products were obtained. Starting with the end-on coordination of the isocyanide to the zirconium centre (2), elevated reaction temperatures and an excess of tert-butylisocyanide resulted after the elimination of the alkyne in the formation of zirconocene η2-iminoacyl cyanide complexes 3a-d. These complexes are formed by coupling with a benzyl fragment through C-H bond activation of a methyl group of methylbenzene. The dimeric cyanide bridged zirconocene complex 4 is formed as a side-product of this process. The unexpected dimer and the heterometallacycles were fully characterised, including X-ray crystallography.