Issue 43, 2022

Synthesis of phosphiranes via organoiron-catalyzed phosphinidene transfer to electron-deficient olefins

Abstract

Herein is reported the structural characterization and scalable preparation of the elusive iron–phosphido complex FpP(tBu)(F) (2-F, Fp = (Fe(η5-C5H5)(CO)2)) and its precursor FpP(tBu)(Cl) (2-Cl) in 51% and 71% yields, respectively. These phosphide complexes are proposed to be relevant to an organoiron catalytic cycle for phosphinidene transfer to electron-deficient alkenes. Examination of their properties led to the discovery of a more efficient catalytic system involving the simple, commercially available organoiron catalyst Fp2. This improved catalysis also enabled the preparation of new phosphiranes with high yields (tBuPCH2CHR; R = CO2Me, 41%; R = CN, 83%; R = 4-biphenyl, 73%; R = SO2Ph, 71%; R = POPh2, 70%; R = 4-pyridyl, 82%; R = 2-pyridyl, 67%; R = PPh3+, 64%) and good diastereoselectivity, demonstrating the feasibility of the phosphinidene group-transfer strategy in synthetic chemistry. Experimental and theoretical studies suggest that the original catalysis involves 2-X as the nucleophile, while for the new Fp2-catalyzed reaction they implicate a diiron–phosphido complex Fp2(PtBu), 4, as the nucleophile which attacks the electron-deficient olefin in the key first P–C bond-forming step. In both systems, the initial nucleophilic attack may be accompanied by favorable five-membered ring formation involving a carbonyl ligand, a (reversible) pathway competitive with formation of the three-membered ring found in the phosphirane product. A novel radical mechanism is suggested for the new Fp2-catalyzed system.

Graphical abstract: Synthesis of phosphiranes via organoiron-catalyzed phosphinidene transfer to electron-deficient olefins

Supplementary files

Article information

Article type
Edge Article
Submitted
07 sept. 2022
Accepted
13 oct. 2022
First published
14 oct. 2022
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2022,13, 12696-12702

Synthesis of phosphiranes via organoiron-catalyzed phosphinidene transfer to electron-deficient olefins

T. Xin, M. B. Geeson, H. Zhu, Z. Qu, S. Grimme and C. C. Cummins, Chem. Sci., 2022, 13, 12696 DOI: 10.1039/D2SC05011K

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