Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 May 24;139(20):6839-6842.
doi: 10.1021/jacs.7b03260. Epub 2017 May 10.

A Biphilic Phosphetane Catalyzes N-N Bond-Forming Cadogan Heterocyclization via PIII/PV═O Redox Cycling

Trevor V Nykaza  1 , Tyler S Harrison  1 , Avipsa Ghosh  1 , Rachel A Putnik  2 , Alexander T Radosevich  1
Affiliations

A Biphilic Phosphetane Catalyzes N-N Bond-Forming Cadogan Heterocyclization via PIII/PV═O Redox Cycling

Trevor V Nykaza et al. J Am Chem Soc. .

Abstract

A small-ring phosphacycle, 1,2,2,3,4,4-hexamethylphosphetane, is found to catalyze deoxygenative N-N bond-forming Cadogan heterocyclization of o-nitrobenzaldimines, o-nitroazobenzenes, and related substrates in the presence of hydrosilane terminal reductant. The reaction provides a chemoselective catalytic synthesis of 2H-indazoles, 2H-benzotriazoles, and related fused heterocyclic systems with good functional group compatibility. On the basis of both stoichiometric and catalytic mechanistic experiments, the reaction is proposed to proceed via catalytic PIII/PV═O cycling, where DFT modeling suggests a turnover-limiting (3+1) cheletropic addition between the phosphetane catalyst and nitroarene substrate. Strain/distortion analysis of the (3+1) transition structure highlights the controlling role of frontier orbital effects underpinning the catalytic performance of the phosphetane.

PubMed Disclaimer

Conflict of interest statement

Notes

The authors declare no competing financial interests.

Figures

Figure 1
Figure 1
Phosphine biphilicity and N–N bond forming Cadogan heterocyclization via PIII/PV=O-catalyzed reductive O-atom transfer.
Figure 2
Figure 2
DFT mechanisms of nitro deoxygenation (M06-2X/6-311++g(d,p)). Relative electronic energies in kcal/mol with unscaled zero-point correction.
Figure 3
Figure 3
Transition structures and distortion/interaction analyses for (3+1)-transition states (M06-2X/6-311++g(d,p)). (A) Phosphetane TS25′ (B) Me3P TS28′. Phosphine distortion energy (ΔEdP‡) in green, nitro-methane distortion energy (ΔEdN‡) in blue, fragment interaction energy (ΔEi‡) in red, activation energy (ΔE‡) in black. All energies in kcal/mol without zero-point correction.
Figure 4
Figure 4
Frontier Kohn-Sham orbital plots and orbital energies for reactant fragments deformed to transition state structures (M06-2X/6-31g(d)).
See this image and copyright information in PMC

References

    1. Rowley AG. In: Organophosphorus Reagents in Organic Synthesis. Cadogan JIG, editor. Academic Press; London: 1979. p. 295.
    1. Maryanoff BE, Reitz AB. Chem Rev. 1989;89:863–927.
    1. Swamy KCK, Kumar NNB, Balaraman E, Kumar KVPP. Chem Rev. 2009;109:2551–2651. - PubMed
    1. Appel R. Angew Chem Int Ed Engl. 1975;14:801–811.
    1. Marsden SP. In: Sustainable Catalysis. Dunn PJ, Hii KK (Mimi), Krische MJ, Williams MT, editors. John Wiley & Sons, Inc; 2013. pp. 339–361.
    2. van Kalkeren HA, van Delft FL, Rutjes FPJT. ChemSusChem. 2013;6:1615–1624. - PubMed
    3. An J, Denton RM, Lambert TH, Nacsa ED. Org Biomol Chem. 2014;12:2993–3003. - PubMed
    4. Voituriez A, Saleh N. Tetrahedron Letters. 2016;57:4443–4451.

Publication types

Substances