Reactivity of Ferrocenyl Phosphates Bearing (Hetero-)Aromatics and [3]Ferrocenophanes toward Anionic Phospho-Fries Rearrangements

Abstract

The temperature-dependent behavior within anionic phospho-Fries rearrangements (apFr) of P(O)(OFc)(EAr) (Fc = Fe(η-CH)(η-CH); E = O; Ar = phenyl, naphthyls, (R)-BINOL, [3]ferrocenophanyl; E = N, 1H-pyrrolyl, 1H-indolyl, 9H-carbazolyl; n = 1-3) is reported. While Fc undergoes one, the Ph-based apFr depends on temperature. First, the aryls are lithiated and rearranged, followed by Fc and N-heterocycles. Addition of MeSO thus gave methylated Fc, contrary to non-organometallic aromatics giving mixtures of HO and MeO derivatives. The (R)-BINOL Fc phosphate gave Fc-rearranged phosphonate in 91% de. Exchanging O- with N-aliphatics prevented apFr, due to higher electron density at P. Also 1,2-N→C migrations were observed. X-ray analysis confirms 1D H bridge bonds for OH and NH derivatives. The differences in reactivity between N-aliphatic and N-aromatic phosphoramidates were verified by electrochemistry. The redox potentials revealed lower values for the electron-rich aliphatics, showing no apFr, preventing a nucleophilic attack at P after lithiation. Redox separations for multiple Fc molecules are based on electrostatic interactions.

(Planar‐Chiral) Ferrocenylmethanols: From Anionic Homo Phospho‐Fries Rearrangements to α‐Ferrocenyl Carbenium Ions

“…Recently electron‐poor pyrrolyl‐, indolyl‐ and carbazolyl‐containing phosphoramidates were converted into stable ferrocenylphosphoramidates . Thus, the CR 2 – O motif was replaced by a CR= N ‐bonded ferrocenyl unit.…”

“…Recently electron-poor pyrrolyl-, indolyl-and carbazolyl-containing phosphoramidates were converted into stable ferrocenylphosphoramidates. [34] Thus, the CR 2 -O motif was replaced by a CR=N-bonded ferrocenyl unit. This imino phosphate motif (type G molecule, Scheme 1) has rarely been described, especially in ferrocene chemistry, where a sole C=N-P(O)Ph 2 unit has been reported, however, without its synthetic procedure.…”

Ferrocenyl‐Pyrenes, Ferrocenyl‐9,10‐Phenanthrenediones, and Ferrocenyl‐9,10‐Dimethoxyphenanthrenes: Charge‐Transfer Studies and SWCNT Functionalization

“…Redox‐active ferrocenyl‐functionalized five‐ and six‐membered heterocycles as well as aromatic and polyaromatic hydrocarbons are well suited as model compounds for studying intramolecular electron transfer processes, as they possess short electron transfer distances. They are easy to functionalize at the heterocyclic or aromatic hydrocarbon core and/or the redox‐active moiety, enabling the straightforward modification of the electronic properties.…”

“…DFT calculations showed that 5b non-covalently interacts with the single-walled carbon nanotube (SWCNT) sidewalls as provenb y, fore xample, disentangling experiments. In addition, CV studies of the as-obtained dispersions confirmed exohedralattachment of 5b at the SWCNTs.Redox-active ferrocenyl-functionalized five- [1] and six-membered [2] heterocyclesa sw ell as aromatic [2][3][4][5] and polyaromatic hydrocarbons [6][7][8][9] are well suited as model compounds for studying intramolecular electron transfer processes,a st hey possess short electron transfer distances. They are easy to functionalize at the heterocyclic or aromatic hydrocarbon core and/or the redox-active moiety,e nabling the straightforward modification of the electronic properties.…”

[1,3]/[1,4]-Sulfur atom migration in β-hydroxyalkylphosphine sulfides

“…In organophosphorus chemistry, rearrangements are less developed transformations, however, some examples can be found in the literature (Scheme 1). These include the famous Arbuzov rearrangement [29][30][31][32] as well as phospha-Fries ( [1,3]-rearrangements) [33][34][35][36][37], phospha-Brook ( [1,2]-rearrangement) [38][39][40][41][42], and [2,3]-sigmatropic rearrangements of propargyl and allylphosphinites [43][44][45][46].…”