Kinetic resolution of chiral cyclohex-2-enones by rhodium(I)/binap-catalyzed 1,2- and 1,4-additions

The feasibility of kinetic resolutions of racemic monosubstituted cyclohex-2-enones by Rh/binap-catalyzed reactions was investigated. 1,2-Addition of AlMe(3) to the 5-substituted derivatives furnished allylic alcohols in the matched case, while the less reactive enantiomers were either left over or transformed into trans-3,5-disubstituted cyclohexanones in parallel or sequential 1,4-additions. Altogether, these represent regiodivergent reactions on racemic mixtures. In contrast, 1,4-addition of aryl groups led to inferior results since either catalyst or substrate control dominated.     

Towards the Antimicrobial Finishing of Poly(isoprene)

Summary: Anionically polymerised (poly)isoprene was functionalized with cysteamine applying thiol-ene click chemistry. Subsequent quaternisation of the primary amino groups gave polymers with antimicrobial activity against Listeria monocytogenes, Eschericchia coli, Pseudomonas fluorescens and Staphylococcus aureus as revealed from tests performed according to the Japanese Industrial Standard Z2801:2000. The novel polymers feature sufficient thermal stability for the compounding with commodity polymers such as poly(propylene) and might be used as a non leaching additive to finish commodity polymers with antimicrobial acitivity.     

Asymmetric cobalt-catalyzed Diels-Alder reactions of a boron-functionalized 1,3-diene with alkynes and allylboration with aldehydes

[Structure: see text] A cobalt(I)-catalyzed Diels-Alder reaction of a 1-boron-functionalized 1,3-diene is the key step in a one-pot reaction interconnecting three simple starting materials to obtain a multifunctionalized product. This product incorporates a stereogenic quaternary center next to a stereogenic secondary alcohol functionality generated with a very high degree of regio- and diastereoselectivity and good enantioselectivity in the presence of a chiral ligand such as (S,S)-Norphos.