Novel Catalytic Hunsdiecker−Heck (CHH) Strategy toward All-<i>E</i> Stereocontrolled Ferrocene-Capped Conjugated Push−Pull Polyenes
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Halodecarboxylation reaction of ferrocenylacrylic acid 1 and ferrocenyldienoic acid 3d with N -bromo- and N -iodosuccinimide in the presence of catalytic tetrabutylammonium trifluoroacetate at −40 °C and −78 °C affords the corresponding β-halovinylferrocenes 2a, 2b and δ-haloferrocenyldiene 4 in 37−72% yields. Heck reaction of β-iodovinylferrocene 2a with vinyl substrates (CH 2 CH−Z where Z = CO 2 Me, CO 2 Et, COMe, CO 2 H, CONH 2, 4‘-NO 2 C 6 H 4 ) in the presence of tri(4-tolyl)arsine/palladium acetate/lithium chloride/triethylamine in acetonitrile at 35−80 °C affords the corresponding ferrocenyldienes 3a − 3f in 50−81% isolated yields. Similar reaction of δ-iodoferrocenyldiene 4 with vinyl substrates (CH 2 CH−Z where Z = CO 2 Me, CO 2 Et, CO 2 H, 4‘-NO 2 C 6 H 4 ) affords the corresponding ferrocenyltrienes 5a − 5d in 55−87% isolated yields. The ferrocene-capped conjugated dienes and trienes show excellent all- E stereoselectivity (vide NMR). The electronic, redox, and nonlinear optical properties of ferrocenylpolyenes have been evaluated. The data suggest that upon increasing the polyene chain length, (a) the absorption maxima shifts progressively to higher wavelength, (b) the oxidation potential of the Fc/Fc + couple ( E 1/2 ) decreases, and (c) the HRS-derived second-order NLO response (β) increases. From the insights derived from semiempirical calculation (ZINDO/1), a mechanism for the halodecarboxylation reaction has been proposed suggesting the prior formation of tetrabutylammonium salt of ferrocenylacrylic acid I . Attack of the halogenium atom at the π C C in I leads to the formation of intermediate II, and the latter triggers the elimination of carbon dioxide.
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Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.020 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it