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 language | English |
|---|---|
| Pages (from-to) | 4028-4048 |
| Number of pages | 21 |
| Journal | European Journal of Inorganic Chemistry |
| Issue number | 34 |
| DOIs | |
| Publication status | Published - 15 Sep 2017 |
| Externally published | Yes |
Cite this
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(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 journal › Article
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 -