Markus Bänziger

A Novel Cathode Material for Cathodic Dehalogenation of 1,1‐Dibromo Cyclopropane Derivatives

Leaded bronze turned out to be an excellent cathode material for the dehalogenation reaction of cyclopropanes without affecting the strained molecular entity. With this particular alloy, beneficial properties of lead cathodes are conserved, whereas the corrosion of cathode is efficiently suppressed. The solvent in the electrolyte determines whether a complete debromination reaction is achieved or if the process can be selectively stopped at the monobromo cyclopropane intermediate. The electroorganic conversion tolerates a variety of functional groups and can be conducted at rather complex substrates like cyclosporine A. This approach allows the sustainable preparation of cyclopropane derivatives.

A facile synthesis of (2R,3E)-4-iodobut-3-en-2-ol and (2S,3E)-4-iodobut-3-en-2-yl chloroacetate

Abstract (2R,3E)-4-Iodobut-3-en-2-ol (( R )- 1 and (2S,3E)-4-Iodobut-3-en-2-yl chloroacetate (( S )- 7 ) of high enantiomeric purity can be prepared by a lipase catalysed kinetic resolution of racemic (E)-4-Iodobut-3-en-2-yl chloroacetate ( 7 ). The alcohol ( R )- 1 can be separated from the ester ( S )- 7 by a simple distillation.

Intriguing influence of the solvent on the regioselectivity of sulfoxide thermolysis in β-amino-α-sulfinyl esters

The sulfoxide thermolysis of the diastereoisomeric methyl (3R,4aS,10aR)-6-methoxy-1-methyl-3-(phenylsulfinyl)-1,2,3,4,4a,5,10,10a-octahydrobenzo[g]quinoline-3-carboxylates 3a and 3′b in toluene yields, by loss of benzenesulfenic acid, an almost 1 : 1 mixture of the vinylogous urethane 2b and the isomeric α-aminomethyl enoate 2a. When this elimination is performed in acetic acid, the enoate 2a is formed rather selectively. The same solvent effects on the regioselectivity of the elimination of benzenesulfenic acid are observed with a simple sulfoxide of ethyl piperidine-3-carboxylate (7).