Jochem Henkelmann

Nucleophilic addition to acetylenes in superbasic catalytic systems: XI. Transformations of alkali metal hydroxides during vinylation of 1-heptanol with acetylene under elevated pressure

Base-catalyzed addition of 1-heptanol to acetylene under elevated pressure of the latter is accompanied by side processes including formation of carboxylic acid salts (alkali metal heptanoates and acetates) with liberation of hydrogen and acetylene polymerization. The rate of acetylene absorption depends on the alkali metal nature and falls down in the series CsOH·H2O ≥ RbOH·H2O > 2KOH·H2O > NaOH > LiOH. Approximately the same order is observed for variation of the rate of deactivation of the catalyst owing to its transformation into metal carboxylate. Dehydration of the catalyst accelerates both vinylation and acetylene polymerization.

An expedient synthesis of methyl vinyl sulfide from dimethyl disulfide and acetylene

Dimethyl disulfide reacts with acetylene under atmospheric pressure in basic reductive systems MOH (M=Na, K)–N2H4u2009·u2009H2O–N-methylpyrrolidone and Na2Su2009·u20099H2O–N2H4u2009·u2009H2O–N-methylpyrrolidone to form methyl vinyl sulfide in up to 79% yield.

Palladium-catalyzed coupling of alkynes with chloroformates to form alkynecarboxylic acid esters

The preparation of alkynecarboxylic acid esters, which are versatile building blocks for the synthesis of heterocyclic compounds, is described by means of the palladium-catalyzed coupling of alkynes with chloroformates for the first time.