Gold‐Catalyzed Hydroarylation of Aryl Alkynylphosphonates for the Synthesis of Phosphacoumarins

Abstract

Intramolecular hydroarylation using aryl alkynylphosphonates proceeds smoothly with a gold/silver catalyst in the presence of trifluoromethanesulfonic acid (TfOH) in the 6‐endo mode, thus affording a unique synthetic method for phosphacoumarins having various functional groups, which could be a privileged structure and prevalent scaffold in phosphorus heterocycles.magnified image

Gold(I)-Catalyzed Activation of Alkynes for the Construction of Molecular Complexity

“… 356 Aryl alkynylphosphonates also undergo intramolecular gold(I)-catalyzed hydroarylation to give phosphacoumarins. 357 …”

Highly Efficient Gold‐Catalyzed Synthesis of Dibenzocycloheptatrienes

“…Substrate 7 i was also prepared and tested under the optimized conditions. Similar molecules were successfully cyclized to phenanthrenes with platinum or gold catalysts in earlier4a, 10 and recent work,3 but unfortunately no conversion was observed (Scheme ). Next, we tried to accelerate the reaction by conducting it at 80 °C in DCE with 5 mol % of [XPhosAu(CH 3 CN)]SbF 6 (because of the superior heat stability of this catalyst)11 and 5 mol % HNTf 2 as additive.…”

Fifty Years of (Benz)oxaphospholene Chemistry

“…[128] Phosphacoumarins 162 were consistently produced in moderate to excellent yields via a6 -endo-dig cyclization. [128] Phosphacoumarins 162 were consistently produced in moderate to excellent yields via a6 -endo-dig cyclization.…”

“…Just ac ouple of months later,L ee's group reportedo nt he Au-catalyzed hydroarylation of aryl alkynylphosphonates 160 (Scheme 40). [128] Phosphacoumarins 162 were consistently produced in moderate to excellent yields via a6 -endo-dig cyclization. However,i nt he case of certain disubstituted aryl derivatives, a5 -exo-dig cyclization mode becamet he dominanto r even exclusive pathway to yield benzoxaphospholenes 161 in decent yields.…”

“…Just a couple of months later, Lee's group reported on the Au‐catalyzed hydroarylation of aryl alkynylphosphonates 160 (Scheme ) . Phosphacoumarins 162 were consistently produced in moderate to excellent yields via a 6 ‐endo ‐dig cyclization.…”