Gold-Catalyzed Access to Isophosphinoline 2-Oxides

Area of Science:

• Organic Chemistry
• Organometallic Chemistry
• Heterocyclic Chemistry

Background:

• Gold(I)-catalyzed reactions involving electron-poor alkynes present synthetic challenges.
• Developing efficient routes to phosphorus-containing heterocycles is of significant interest.

Purpose of the Study:

• To report a straightforward synthesis of 2-phenyl 1H-isophosphinoline 2-oxides.
• To establish a regioselective method for constructing phosphorus heterocycles.

Main Methods:

• Utilized a PPh3AuCl precatalyst in conjunction with triflic acid.
• Employed microwave irradiation to accelerate the reaction.
• Investigated a 6-endo-dig hydroarylation cyclization pathway.

Main Results:

• Achieved moderate to quantitative yields of isophosphinoline 2-oxides.
• Demonstrated full regioselectivity in the cyclization process.
• Successfully synthesized phosphorus-based heterocycles.

Conclusions:

• The developed method offers an effective strategy for synthesizing phosphorus heterocycles.
• This work expands the scope of gold-catalyzed alkyne functionalization.
• The regioselective hydroarylation cyclization provides a valuable synthetic tool.