1,6-Carbene transfer: gold-catalyzed oxidative diyne cyclizations.

In the presence of a gold catalyst an unprecedented oxidative cyclization of diynes takes place. The reaction cascade is initiated by an oxygen transfer from a N-oxide onto a gold-activated alkyne. The formed α-oxo carbene is transferred across the second alkyne yielding a stabilized vinyl carbene/cation.

Gold-catalyzed synthesis of iodofulvenes.

We report the gold-catalyzed synthesis of highly functionalized iodofulvenes from iododialkynes under mild conditions. The catalytic cycle involves the formation of gold acetylides and vinylgold intermediates. These intermediates can then undergo an unprecedented iodine/gold exchange.

Dual gold catalysis: σ,π-propyne acetylide and hydroxyl-bridged digold complexes as easy-to-prepare and easy-to-handle precatalysts.

A series of dinuclear gold σ,π-propyne acetylide complexes were prepared and tested for their catalytic ability in dual gold catalysis that was based on the reaction of an electrophilic π-complex of gold with a gold acetylide. The air-stable and storable catalysts can be isolated as silver-free catalysts in their activated form. These dual catalysts allow a fast initiation phase for the dual catalytic cycles without the need for additional additives for acetylide formation.