Robert W. Lang

New fluorinating reagents - I. The first enantioselective fluorination reaction

Abstract Crystalline, optically pure N-fluoro sultams (−)-3 and (+)-5 are the first examples of enantioselective fluorinating reagents. Thus unprecedented enantiomeric excesses up to 70% are observed when various prochiral metal enolates are fluorinated by using these new reagents.

Fluorine-containing organozinc reagents. IV.: Reformatskii-type reactions of chlorodifluoroacet1c acid derivatives

Abstract Chlorodifluoroacetic acid has shown to be a promising starting material for Reformatskii-type syntheses of fluorine-containing molecules and thus, it offers an attractive extension to what is known from rather expensive bromodifluoroacetic acid.

Selective mono- and difluorination of enolates

The selective transformation of enolates into mono- and difluorinated carbonyl compounds can be performed in a one-pot procedure using N-F-sultam 1. The yields and the selectivity of the fluorination strongly depend on the counterion of the enolate and the acidity of the proton α to the carbonyl group.

Fluorine-containing organozinc reagents. V.: The reformatskii-claisen reaction of chlorodifluoroacetic acid derivatives

Abstract Silicon induced Reformatskii-Claisen reaction of allyl chlorodifluoroacetate ( 1 ) affords 2,2-difluoro-4-pentenoic acid ( 2 ) in good yields. Starting from inexpensive chloro-difluoroacetic acid, a variety of useful fluorine-containing synthetic building blocks can be obtained under the same reaction conditions.

Fluorine-containing organozinc reagents - VI. The preparation of α-Trifluoromethyl-α,β-unsaturated carboxylic acid esters☆

Abstract The Reformatzky reaction of the readily available methyl 2,2-dichloro-3,3,3-trifluoropropionate with aldehydes followed by acylation and reductive elimination in situ constitutes a general synthetic scheme for the preparation of methyl α-trifluoromethyl-α,β-unsaturated carboxylates, useful as fluorine-containing building blocks.

Fluorine-containing organozinc reagents. II: The crystal structure of (1,1-dichloro-2,2,2-trifluoroethylzinc chloride)•2(dimethylformamide)

Abstract The DMF complex of 1, 1-dichloro-2, 2, 2-trifluoroethylzinc chloride, a key intermediate in the one pot synthesis of CF 3 CCl 2 -substituted alcohols, has been isolated and its structure determined by 13 C NMR spectroscopy and by X-ray diffraction. This is the first X-ray structural study of a perhalogenated alkylzinc halide and the results show the DMF complex to be monomeric.