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. Alkyl migration or sp(3)-CH insertion then terminates the catalytic cycle by formation of highly substituted functionalized indenones. A 1,6-carbene shift could be supported by the oxidation of the vinyl carbene. This protocol represents an attractive alternative to procedures which are based on the metal-catalyzed decomposition of hazardous, not easily accessible, diazo compounds.
Organisch-Chemisches Institut, Ruprecht-Karls-Universität Heidelberg , Im Neuenheimer Feld 270, 69221 Heidelberg, Germany.
Pascal
P
Nösel
Laura Nunes
LN
dos Santos Comprido
Tobias
T
Lauterbach
Matthias
M
Rudolph
Frank
F
Rominger
A Stephen K
AS
Hashmi