Richard Göttlich

Copper(I) Catalysts for the Stereoselective Addition ofN-Chloroamines to Double Bonds: A Diastereoselective Radical Cyclisation

Copper(I) catalysts for the diastereoselective radical cyclisation of N-chloro-N-pentenylamines have been developed. The stereoselectivity of the cyclisation depends upon the ligands employed, proving that the radical is bound to the catalyst during the formation of the new stereocentre and making a catalyst-influenced stereoselective radical reaction possible. The influence of the catalyst on the Beckwith−Houk transition states is discussed. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Iodide-Catalysed Cyclization of Unsaturated N-Chloroamines: A New Way to Synthesise 3-Chloropiperidines

Tetrabutylammonium iodide is a very efficient catalyst for the cyclization of unsaturated N-chloroamines. The catalysis seems to proceed through N-iodoamine intermediates, which act as a source of iodonium ions. (© Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)

Conformer Equilibria in 2,4-Disubstituted Pentane Derivatives

2,4-Disubstituted pentanes are molecules which adopt essentially only two conformations. Substituents have been varied in order to find those which lead to a strong preference of the conformer equilibrium. Studying 2-substituted 4-methylpentanes 3 and 4-benzyloxypentanes 12, it has been shown that substituent effects on the conformer equilibria are not additive, as would be expected on the grounds of steric effects alone. Rather, interactions between polar groups reinforce the bias of the conformer equilibria. When applied to 2,4-disubstituted pentanes, substituents such as chloro or phthalimido shift the conformer equilibrium to the side of the gg conformer with preferences exceeding 90%.

Conformation Induction Between Neighboring Dimethylpentane Segments

A 2,4-dimethylpentane unit can be rendered monoconformational by the presence of a conformation-inducing group (an inductor group) at C-1 (cf. 6). The resulting entity may serve as an inductor group to control in turn the conformation of a neighboring dimethylpentane segment (cf. 7). This holds if the inducing dimethylpentane segment is isotactic (cf. 15, 25), but not when it is syndiotactic (cf. 28).

Copper(I) catalysed cyclisation of unsaturated N-benzoyloxyamines: an aminohydroxylation via radicals

A new catalytic aminohydroxylation via radicals has been developed leading to cyclic aminoalcohols.

Open chain compounds with preferredconformations

The shape of a flexible molecule, i.e. the preferred conformation of a multi-substituted alkyl chain, may be controlled by the nature and location of the pendant substituents. Steric interactions between those substituents themselves as well as the main chain, or sterically demanding end-groups, can be used to realize conformation design of flexible molecules.

A new catalytic hetero-Heck type reaction

Unsaturated N-chloroamines have been found to cyclise under palladium-catalysis in good yield, the proposed mechanism includes an oxidative addition of the chloroamine to Pd(0), thus opening a new entry to the amides of the late transition metals.

Intermolecular addition reactions of N-alkyl-N-chlorosulfonamides to unsaturated compounds

Summary N-Alkyl-N-chlorosulfonamides add to alkenes under copper(I) catalysis. In reactions of styrene derivatives with terminal double bonds the addition products were obtained in excellent yield and high regioselectivity. Lower yields are obtained in addition reactions to non-aromatic alkenes. The reaction most likely proceeds via a redox catalysis and amidyl radicals, a concerted mechanism has been ruled out and a polar mechanism via chloronium ions would lead to the opposite regiochemistry.

FLEXIBLE MOLECULES WITH DEFINED SHAPE. PART 5. CONFORMATIONAL ANALYSIS OF 2,4,6,N-POLYMETHYLATED ALKANE DERIVATIVES

Poly-2,4,6,n-methylated undecene-(3–6) and pentadecene-derivatives(8–11) have been synthesized. In these compounds each backbone segment displays local bi-conformational behaviour. The effect of oxygen-substituents on the conformer population of the individual backbone segments has been studied by evaluating 3JH,H and 3JC,C coupling constants.