Michal Fedorynski

Time-resolved flash spectroscopic investigations of the reactions of singlet arylhalocarbenes

Abstract The results of time-resolved laser flash spectrometric studies of singlet arylhalocarbenes are reviewed. In particular, the absolute rate constants for reactions of phenylchlorocarbene and related carbenes with alkenes are summarized and systematized. The experiments described provide the basis for a detailed examination of carbenic reactivity-selectivity principles. The results of studies on the influence of temperature on the absolute rate constants for carbene reactions are consistent with the existence of transient carbene/alkene intermediates.

Fluoromethoxydiazirine and fluoromethoxycarbene

Abstract 3-Fluoro-3-methoxydiazirine was synthesized in ~35% overall yield in a two-step procedure that eschews elemental fluorine.

Exchange reactions of diazirines: 3-X-3-methyldiazirines and derived carbenes

Abstract 3-Bromo-3-methyldiazirine readily undergoes exchange reactions with F − , MeO − , CN − , or N 3 − . New carbene precursors can thus be prepared.

Phase transfer catalyzed (PTC) reactions of chloroform with alkenyl carboxylates. Effect of catalyst structure on reaction course

Reaction of chloroform with ketone enol eters 1d,e carried out in the presence of 50% aq NaOH and benzyltriethylammonium chloride (TEBAC) as a catalyst gives gem-dichlorocyclopropanes 3d,e. In the case of enol esters of aldehydes, adducts of trichloromethyl anion 2a,b,f,h (from 1a,b,f,h) or mixtures of 2 and 3 (from 1c,g,i) are formed. the same reaction carried out with a catalytic amount of tetramethylammonium hydrogen sulphate (TMAHS) yields mixtures of 2 and 3, highly enriched in the latter products, or pure 3i from 1i. The kind of the products formed depends on ease of cleavage of 1 by base, nucleophilicity of carboncarbon double bond in 1, and type of the catalyst applied.