Remote stereochemical control in asymmetric Diels-Alder reactions: synthesis of the angucycline antibiotics, (−)-tetrangomycin and MM 47755

The first asymmetric syntheses of the angucycline antibiotics, (−)-tetrangomycin and MM 47755, are achieved via a short efficient sequence starting from the chiral Lewis acid promoted Diels-Alder reaction of 5-hydroxy-1,4-naphthoquinone and (±)-(E)-5-dimethylphenylsilyl-5-methyl-1-(2′-trimethylsiloxyvinyl)cyclohexene 7 where an effective kinetic resolution of the latter, controlled by its remote stereocentre, is described.     

Using a variable production rate as a response mechanism in the economic production lot size model

In this paper we consider a variant of the well known EPL model where the production rate is a decision variable. We show that the following response mechanism can be optimal, namely as a response to an increased demand rate to decrease the production rate.     

Cyclic homology of Dedekind domains

We compute the cyclic homology of the algebraR[t]/(P(t)) relative to an arbitrary integral domainR. As an application, we compute the cyclic homology of number rings.Supported by N.S.F. Grant No. DMS-8807203.     

Engleromycin, a new cytochalasan from Hennings

The structure of engleromycin isolated from Hennings has been established as by spectral techniques.     

Computer-assisted chromatogram evaluation in dual capillary gas chromatography

Gas-chromatographic analysis of complex mixtures is simplified enormously by the use of the simultaneous dual capillary technique. The advantages over a single-column system are that the components are more reliably identified and quantified. After integration has taken place, the data from both capillaries are cor-related with the aid of a computer program whose principles are described.