Elke Fritz-Langhals

Synthesis of aromatic aldehydes by laccase-mediator assisted oxidation

Abstract Aromatic aldehydes can be prepared in aqueous medium by oxidation of the corresponding methyl aromatic compounds in the presence of oxygen, the enzyme laccase and catalytic amounts of various N-hydroxy compounds. Allylic alcohols also gave the corresponding aldehydes in good yield. Competing reactions reveal that the N-hydroxy compounds is involved in the rate determining step of the reaction.

Simple synthesis of optically active 2-fluoropropanoic acid and analogs of high enantiomeric purity

A very simple synthesis of optically active 2-fluoropropanoic acid 1 (R=CH3, R′=H) and analogs of high enantiomeric purity was developed using the sulfonates 2 of the corresponding optically active 2-hydroxycar☐ylic esters and potassium fluoride in formamide. Thus methyl (R)-2-fluoropropanoate (1, R=CH3, R′=CH3) was prepared in an optical purity of 96% from the mesylate of methyl (S)-lactate (ee 97.4 %) and isolated in 83% yield.

Synthesis of optically active 1-fluoroalkyl benzenes

Abstract A simple synthesis of optically active 1-fluoroalkyl benzenes bearing electron withdrawing substituents is developed. Optically active 1-hydroxyalkyl benzenes are converted into the methanesulfonates and subsequently converted into the optically active 1-fluoroalkyl benzenes 1 by use of the fluorinating agent cesium fluoride/N-methyl-formamide.

Aldehyde and Carboxy Functional Polysiloxanes

Aldehyde functional polysiloxanes (1) (Fig. 1) can be selectively prepared in high yield and purity by oxidation of the corresponding carbinols with -technical bleach and catalytic amounts of TEMPO. This simple oxidation method is also successfully used for the preparation of the corresponding carboxylic acids 2 (Fig. 1). The stability, reactivity and chemical properties of new compounds 1 and 2 are -investigated.