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

Marcus Korb, Julia Mahrholdt, Heinrich Lang

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The reaction of FcCH(2)OH with chlorophosphates gave ferrocenyl phosphates FcCH(2)OP(O)(OR)(2) [Fc = Fe(eta(5)-C5H5)(eta(4)-C5H4)], which readily separate into phosphate anions and ferrocenyl carbo-cations. The latter species undergoes consecutive reactions, for example, electrophilic aromatic substitutions. When nitriles, instead of alcohols, are treated with FcLi or tBuLi and chlorophosphates, chiral-pool based ferrocenylimino phosphoramidates Fc-CR=N-P(O)(OR*)(2) are formed, which are promising candidates for anionic homo phospho-Fries rearrangements. Moreover, the sterically demanding chiral chlorophosphate with R* enabled oxidative couplings of the imines to form a diferrocenylazine. Similarly, the reaction of Fc-Li with 9-anthrylnitrile produced a 10-ferrocenyl-substituted product, contrary to a reaction at the C equivalent to N functionality. A planar-chiral ortho-P(S)Ph-2-functionalized ferrocenylmethanol also gave carbo-cations under acidic conditions. These species can be sulfurized in a unique way giving thio ethers, whereby the in situ formed 1,2-P(S)Ph-2,CH2+ ferrocene cation acts as the sulfur and electron source. However, lowering the substrate concentration prevents sulfur migration, resulting in electrophilic substitution reactions with aromatic solvents. Planar-chiral ferrocenylmethyl thio or anisyl derivatives were applied as ligands in Pd-catalyzed Suzuki-Miyaura C,C cross-couplings for the atroposelective synthesis of hindered biaryls with up to 26% ee at low catalyst loadings (1 mol-% Pd).

Original languageEnglish
Pages (from-to)4028-4048
Number of pages21
JournalEuropean Journal of Inorganic Chemistry
Issue number34
DOIs
Publication statusPublished - 15 Sep 2017
Externally publishedYes

Cite this

@article{4de1f44fb7d94a208ca94f3970fa847e,
title = "(Planar-Chiral) Ferrocenylmethanols: From Anionic Homo Phospho-Fries Rearrangements to -Ferrocenyl Carbenium Ions",
abstract = "The reaction of FcCH(2)OH with chlorophosphates gave ferrocenyl phosphates FcCH(2)OP(O)(OR)(2) [Fc = Fe(eta(5)-C5H5)(eta(4)-C5H4)], which readily separate into phosphate anions and ferrocenyl carbo-cations. The latter species undergoes consecutive reactions, for example, electrophilic aromatic substitutions. When nitriles, instead of alcohols, are treated with FcLi or tBuLi and chlorophosphates, chiral-pool based ferrocenylimino phosphoramidates Fc-CR=N-P(O)(OR*)(2) are formed, which are promising candidates for anionic homo phospho-Fries rearrangements. Moreover, the sterically demanding chiral chlorophosphate with R* enabled oxidative couplings of the imines to form a diferrocenylazine. Similarly, the reaction of Fc-Li with 9-anthrylnitrile produced a 10-ferrocenyl-substituted product, contrary to a reaction at the C equivalent to N functionality. A planar-chiral ortho-P(S)Ph-2-functionalized ferrocenylmethanol also gave carbo-cations under acidic conditions. These species can be sulfurized in a unique way giving thio ethers, whereby the in situ formed 1,2-P(S)Ph-2,CH2+ ferrocene cation acts as the sulfur and electron source. However, lowering the substrate concentration prevents sulfur migration, resulting in electrophilic substitution reactions with aromatic solvents. Planar-chiral ferrocenylmethyl thio or anisyl derivatives were applied as ligands in Pd-catalyzed Suzuki-Miyaura C,C cross-couplings for the atroposelective synthesis of hindered biaryls with up to 26{\%} ee at low catalyst loadings (1 mol-{\%} Pd).",
keywords = "Ferrocenes, Phosphorus, Iron, Sulfur, Cross-coupling, CARBON BOND FORMATION, C-13 NMR-SPECTRA, STRUCTURAL-CHARACTERIZATION, ASYMMETRIC-SYNTHESIS, ELECTROPHILIC SUBSTITUTION, CERIUM(III) CHLORIDE, NONAQUEOUS SOLVENTS, DELTA-E-1/2 VALUES, REACTION CHEMISTRY, CRYSTAL-STRUCTURE",
author = "Marcus Korb and Julia Mahrholdt and Heinrich Lang",
year = "2017",
month = "9",
day = "15",
doi = "10.1002/ejic.201700645",
language = "English",
pages = "4028--4048",
journal = "European Journal of Inorganic Chemistry",
issn = "1099-0682",
publisher = "Wiley-VCH Verlag GmbH & Co. KGaA",
number = "34",

}

(Planar-Chiral) Ferrocenylmethanols : From Anionic Homo Phospho-Fries Rearrangements to -Ferrocenyl Carbenium Ions. / Korb, Marcus; Mahrholdt, Julia; Lang, Heinrich.

In: European Journal of Inorganic Chemistry, No. 34, 15.09.2017, p. 4028-4048.

Research output: Contribution to journalArticle

TY - JOUR

T1 - (Planar-Chiral) Ferrocenylmethanols

T2 - From Anionic Homo Phospho-Fries Rearrangements to -Ferrocenyl Carbenium Ions

AU - Korb, Marcus

AU - Mahrholdt, Julia

AU - Lang, Heinrich

PY - 2017/9/15

Y1 - 2017/9/15

N2 - The reaction of FcCH(2)OH with chlorophosphates gave ferrocenyl phosphates FcCH(2)OP(O)(OR)(2) [Fc = Fe(eta(5)-C5H5)(eta(4)-C5H4)], which readily separate into phosphate anions and ferrocenyl carbo-cations. The latter species undergoes consecutive reactions, for example, electrophilic aromatic substitutions. When nitriles, instead of alcohols, are treated with FcLi or tBuLi and chlorophosphates, chiral-pool based ferrocenylimino phosphoramidates Fc-CR=N-P(O)(OR*)(2) are formed, which are promising candidates for anionic homo phospho-Fries rearrangements. Moreover, the sterically demanding chiral chlorophosphate with R* enabled oxidative couplings of the imines to form a diferrocenylazine. Similarly, the reaction of Fc-Li with 9-anthrylnitrile produced a 10-ferrocenyl-substituted product, contrary to a reaction at the C equivalent to N functionality. A planar-chiral ortho-P(S)Ph-2-functionalized ferrocenylmethanol also gave carbo-cations under acidic conditions. These species can be sulfurized in a unique way giving thio ethers, whereby the in situ formed 1,2-P(S)Ph-2,CH2+ ferrocene cation acts as the sulfur and electron source. However, lowering the substrate concentration prevents sulfur migration, resulting in electrophilic substitution reactions with aromatic solvents. Planar-chiral ferrocenylmethyl thio or anisyl derivatives were applied as ligands in Pd-catalyzed Suzuki-Miyaura C,C cross-couplings for the atroposelective synthesis of hindered biaryls with up to 26% ee at low catalyst loadings (1 mol-% Pd).

AB - The reaction of FcCH(2)OH with chlorophosphates gave ferrocenyl phosphates FcCH(2)OP(O)(OR)(2) [Fc = Fe(eta(5)-C5H5)(eta(4)-C5H4)], which readily separate into phosphate anions and ferrocenyl carbo-cations. The latter species undergoes consecutive reactions, for example, electrophilic aromatic substitutions. When nitriles, instead of alcohols, are treated with FcLi or tBuLi and chlorophosphates, chiral-pool based ferrocenylimino phosphoramidates Fc-CR=N-P(O)(OR*)(2) are formed, which are promising candidates for anionic homo phospho-Fries rearrangements. Moreover, the sterically demanding chiral chlorophosphate with R* enabled oxidative couplings of the imines to form a diferrocenylazine. Similarly, the reaction of Fc-Li with 9-anthrylnitrile produced a 10-ferrocenyl-substituted product, contrary to a reaction at the C equivalent to N functionality. A planar-chiral ortho-P(S)Ph-2-functionalized ferrocenylmethanol also gave carbo-cations under acidic conditions. These species can be sulfurized in a unique way giving thio ethers, whereby the in situ formed 1,2-P(S)Ph-2,CH2+ ferrocene cation acts as the sulfur and electron source. However, lowering the substrate concentration prevents sulfur migration, resulting in electrophilic substitution reactions with aromatic solvents. Planar-chiral ferrocenylmethyl thio or anisyl derivatives were applied as ligands in Pd-catalyzed Suzuki-Miyaura C,C cross-couplings for the atroposelective synthesis of hindered biaryls with up to 26% ee at low catalyst loadings (1 mol-% Pd).

KW - Ferrocenes

KW - Phosphorus

KW - Iron

KW - Sulfur

KW - Cross-coupling

KW - CARBON BOND FORMATION

KW - C-13 NMR-SPECTRA

KW - STRUCTURAL-CHARACTERIZATION

KW - ASYMMETRIC-SYNTHESIS

KW - ELECTROPHILIC SUBSTITUTION

KW - CERIUM(III) CHLORIDE

KW - NONAQUEOUS SOLVENTS

KW - DELTA-E-1/2 VALUES

KW - REACTION CHEMISTRY

KW - CRYSTAL-STRUCTURE

U2 - 10.1002/ejic.201700645

DO - 10.1002/ejic.201700645

M3 - Article

SP - 4028

EP - 4048

JO - European Journal of Inorganic Chemistry

JF - European Journal of Inorganic Chemistry

SN - 1099-0682

IS - 34

ER -