[6+3] Cycloaddition of Fischer aminocarbene complexes: An efficient annulation of fulvenes to indene derivatives

Transition metals in organic synthesis: Highlights for the year 2005

“…(403)) [1601]. [1602]. Irradiation of imino Fischer chromium carbenes in the presence of an alkyne affords different products depending on the alkyne (Eq.…”

Versatile Reactivity of Alkynyl Fischer Carbene Complexes toward Pentafulvenes: Carbocyclization and C−H Insertion Reactions

“…[4+3] Cycloaddition of Alkynyl Carbene Complexes and Pentafulvenes. It was found that the reaction of alkynyl carbene complexes of tungsten and pentafulvenes can be efficiently driven to the [4+3] cyclization pathway by running the reaction under CO (20 bar) (Scheme ). 21b, Moreover, after screening a diversity of solvents, hexane and DMF were chosen for the reaction with 6-substituted 3a − e and 6,6-disubstituted pentafulvenes 3f − h , respectively. Thus, phenylethynyl(methoxy)carbene complex 1a was reacted, under a CO atmosphere (20 bar), with monosubstituted fulvenes 3a − e in hexane at 60 °C.…”

“…More recently, new models of reactivity for Fischer carbenes have been discovered when particular unsaturated substrates such as pentafulvenes 20 are used (see Figure for 6,6-dimethylfulvene) . Thus, using simple carbene complexes results in the cyclopropanation of the endocyclic carbon−carbon double bond (path a), while a [6+3] cyclization involving the whole π-framework of the fulvene structure takes place with alkenyl carbene complexes (path b).…”

Synthesis of nitrogen‐containing compounds using chromium Fischer carbene complexes

“…Although the chemistry of alkoxy carbene complexes has been studied extensively and these complexes have been well recognized as useful tools in synthetic organic chemistry, the chemistry of the corresponding amino carbene complexes is relatively underdeveloped 26. Although several annulation reactions of amino carbene complexes with alkynes and/or CO ligands have been reported in recent years,27 there have been few studies of the reactions of amino carbene complexes with other functionalities such as olefins 28,27c…”