Chemoselective Carbophilic Addition of α‐Diazoesters through Ligand‐Controlled Gold Catalysis

Abstract

The chemoselective addition of arenes and 1,3-diketones to α-aryldiazoesters was achieved through ligand-controlled gold catalysis. Unlike a dirhodium catalyst (which promotes C(sp3)-H insertion and cyclopropanation) and a copper catalyst (which catalyzes O-H and N-H insertions), the gold catalyst with an electron-deficient phosphite as the ancillary ligand exclusively gave the carbophilic addition product, thus representing a new and efficient approach to form "carbophilic carbocations", which selectively react with carbon nucleophiles.

A Desulfonylative Approach in Oxidative Gold Catalysis: Regiospecific Access to Donor‐Substituted Acyl Gold Carbenes

“…This strategy permits ready explorations of these reactive intermediates without resorting to hazardous and potentially explosive diazo ketone precursor, [3] and thereby facilitates the development of various versatile synthetic methods. [2, 4],[5] While terminal alkynes are most frequently oxidized to terminal gold carbene intermediates, regioselective oxidations of internal alkynes can be challenging, and often only one regioisomer could be accessed selectively based on structural biases and upon optimizations of catalyst, oxidant and other reaction conditions.…”

The chemistry of the carbon-transition metal double and triple bond: Annual survey covering the year 2014

“…Isocyanide-assisted O-H insertion reactions of diazo-derived copper carbenoids were suggested to proceed via ylide formation with the imino-anhydride generated from the carboxylic acid-isocyanide coupling [1289]. A hindered phosphite gold complex proved highly selective for C-H insertion over O-H insertion or cyclopropanation in the reaction of α-diazo esters with phenol or other electron rich aromatic substrates [1290,1291]. Cyclopropanation using magnetically-removable copper plated iron nanoparticles was also reported [1292,1293].…”

Distant C-H Activation/Functionalization: A New Horizon of Selectivity Beyond Proximity

“…Xi et al reported (ArO) 3 PAuNTf 2 catalyzed carbophilic addition of α-diazoesters at para-position of phenol derivatives (Scheme 54) (91). Aniline also reacted albeit in low yield.…”