Gold‐Catalyzed Formal Dehydro‐Diels–Alder Reactions of Ene‐Ynamide Derivatives Bearing Terminal Alkyne Chains: Scope and Mechanistic Studies

Abstract

A new protocol for the synthesis of a variety of N-containing aromatic heterocycles by a formal gold-catalyzed dehydro-Diels-Alder reaction of ynamide derivatives has been developed. Deuterium-labeling experiments and kinetic studies support the involvement of a dual gold catalysis mechanism in which a gold acetylide moiety adds onto an aurated keteneiminium.

Rhodium-catalysed tetradehydro-Diels–Alder reactions of enediynes via a rhodium-stabilized cyclic allene

“…For example, several recent reports have harnessed dual gold-catalysts in cycloaromatisations via TDDA reactions of enediynes. [3][4][5][6][7] In these cases the enediyne is not fully conjugated but has the alkyne and enyne units linked via a heteroatom tether leading to a diverse range of fused heterocyclic benzenoid structures of biological signicance (Scheme 1b).…”

Dual Gold‐Catalyzed Formal Tetradehydro‐Diels–Alder Reactions for the Synthesis of Carbazoles and Indolines

“…[1n] Al ot of fundamental studies on thermalt etradehydro-Diels-Alder (TDDA) reactions [3] have been reportedr ecently.T hese providedapowerful strategy to de novo synthesis of benzenoids;h owever,t he harsh reactionc onditions, such as high temperature, diluted reaction concentrations, and requirement of polymerization inhibitors, make them difficult to be used in practical synthesis (Scheme 1b). [3] Taking advantage of the ability of Au complexes to activatea lkynes in catalytic processes, [4] Liu recently reported ag old-catalyzedT DDA reaction [5] under mild reaction conditions. Aw idened substrate scope was achieved compared to thermal tetradehydro-Diels-Alder (TDDA) reactions.…”

Gold‐Catalyzed Annulations of N‐Propargyl Ynamides with Anthranils with Two Distinct Chemoselectivities

“…Ta ble 1s hows the reactions of N-tosyl propargyl ynamide [14] (1a)withanthranil [11a, 15] (2a)byusing various metallic catalysts. In entries 1-10, the resulting dichloroethane (DCE) solution was washed with an aqueousH Cl solution (1 m)t oe nsure complete hydrolysis of its ketone-derived imine 3a' (see below,T able 5).…”