Oliver Krebs

Allylic Amidation of Olefins by Ene Reaction of Acylnitroso Compounds Generated in situ by Oxidation of Hydroxamic Acids

A one-pot allylic amidation procedure, which employs the ene reaction of acylnitroso compounds 2 with electron-rich olefins 3a,b, is presented; the acylnitroso enophile is generated in situ by oxidation of hydroxamic acids 1 with iodosobenzene diacetate. The resulting N-allylhydroxamic acids 4 (ene products) are quantitatively acetylated for ease of handling; as an example, the reduction of the acetylated derivative 5b by samarium diiodide was carried out to afford the N-allyl amide 6b in quantitative yields.

A Comparative Study on the Diastereofacial Control in the [4+2] Cycloaddition of Sorbates and the Ene Reaction of Tiglates with Singlet Oxygen and PTAD by a Variety of Chiral Auxiliaries

The auxiliary-induced diastereoselectivities of [4+2] cycloaddition and the ene reaction of singlet oxygen and PTAD through a variety of auxiliaries is studied. The different trends in the diastereoselectivities that are observed for the diverse auxiliaries, which include 2,2-dimethyloxazolidines, a menthol derivative, several related cyclohexanes, and the Oppolzer sultam, are compared and backed by mechanistic interpretations. From this overview of two reaction modes for two electrophiles and four different types of auxiliaries, the advantages of the individual auxiliaries become evident and comprehensible. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

How deep is your love? A quantitative spatial analysis of the transatlantic trade partnership

This paper explores the quantitative consequences of transatlantic trade liberalization envisioned in a Transatlantic Trade and Investment Partnership (TTIP) between the United States and the European Union. Our key innovation is to develop a new quantitative spatial trade model and to use an associated technique which is extraordinarily parsimonious and tightly connects theory and data. We take input-output linkages across industries into account and make use of the recently established World Input Output Database (WIOD). We also explore the consequences of labor mobility across local labor markets in Germany and the countries of the European Union. We address the considerable uncertainties connected both with the quantification of non-tariff trade barriers and the outcome of the negotiations by taking a corridor of trade liberalization paths into account.