Addition reactions of a phosphorus triamide to nitrosoarenes and acylpyridines

Abstract

Tricoordinate phosphorus compounds react with a wide variety of double bonds through addition reactions. The dipolar and cyclic products formed are important intermediates in organophosphorus chemistry. We investigated the reactivity between phosphorus triamide 1 and nitrosoarenes and 2-acylpyridines. For sterically congested substrates, the formation of σ⁵,λ⁵-phosphorus products is observed. DFT calculations indicate this product is formed through a concerted [4 + 1] mechanism. For less sterically congested substrates, products are observed arising from cleavage of the N = O or C = O bond with formation of a terminal P = O bond and aryl nitrene or carbene migration into a P–N bond of the phosphorus triamide core. DFT calculations are consistent with an initial [2 + 1] addition to phosphorus followed by formal carbene/nitrene migration in these cases.

GRAPHICAL ABSTRACT

Keywords:

• Acylpyridine
• addition reaction
• DFT calculations
• nitrosoarene
• phosphorus

Acknowledgment

We thank Dr. Peter Muller (MIT) for assistance with crystallographic data collection and structure elucidation of compound 6.

Additional information

Funding

Funding for synthetic chemistry was provided by NSF (CHE-1900060). This work was supported by The Netherlands Organization for Scientific Research (Rubicon Postdoctoral Fellowship 019.181EN.020 to CtG). ChemMatCARS Sector 15 is principally supported by the Divisions of Chemistry (CHE) and Materials Research (DMR), National Science Foundation, under grant number NSF/CHE1346572. Use of the PILATUS3 X CdTe 1M detector is supported by the National Science Foundation under the grant number NSF/DMR-1531283. Use of the Advanced Photon Source, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.