Predicting experimental yields as an index to rank synthesis routes: application for Diels–Alder reactions

Hori, Kenzi; Sakamoto, Makoto; Yamaguchi, Toru; Sumimoto, Michinori; Okano, Katsuhiko; Yamamoto, Hiroyuki

doi:10.1016/j.tet.2007.11.108

Cited by 6 publications

(6 citation statements)

References 17 publications

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“…Unfortunately, we could obtain no clear relationship between the Z obs and Z calc . Because some TSs for Diels–Alder reactions take structures different from their typical geometry, we excluded such data from the PLS regression in the previous study . According to the distances in Table , there were no TSs that took structures that deviated from the ordinal TS geometry of the Curtius rearrangement.…”

Section: Resultsmentioning

confidence: 99%

“…It is likely that PLS regression can create an equation connecting the experimental yields with the calculated E a ( calc ) values and the experimental conditions because we previously succeeded in predicting the yields of Diels–Alder reactions . Therefore, PLS regression was used to correlate the Z obs with these explanatory variables using Eqn (7)

\begin{matrix} Z_{italicobs} = I n (I n (C_{0} / C)) \\ ≅ a ln ε + β I n t + γ (- E_{a} (c a l c) / R T) + δ \\ = Z_{italiccalc} \end{matrix}

…”

Section: Methods Of Calculationsmentioning

confidence: 99%

“…This equation includes E a ( calc ), the logarithm of the dielectric constant of the solvent ε, the reaction time t F , T and the constant δ. We adopted these parameters because principal component analysis in a previous study showed that these four descriptors are important for modeling the experimental yields . In the present study, the Z calc value is calculated on the basis of experimental data of the Curtius rearrangement.…”

Section: Methods Of Calculationsmentioning

confidence: 99%

“…The partial least squares (PLS) regression was adopted to obtain a relationship between calculated activation energies ( E a ) and experimental yields. It was confirmed that this statistical method produces a good model equation that can predict experimental yields for the Diels–Alder reaction, a typical second‐order reaction . However, there are no guarantees that the same method is applicable to first‐order reactions.…”

Section: Introductionmentioning

confidence: 94%

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Predicting experimental yields as an index to rank synthesis routes II: application to the Curtius rearrangement

Yoshimura

Okano

Ishikawa

et al. 2011

J of Physical Organic Chem

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Synthesis yields of organic reactions are one of the most important factors in ranking synthesis routes created by synthesis route design systems such as Transform-Oriented Synthesis Planning and Knowledge base-Oriented Synthesis Planning. If it is possible to predict the yields of synthesis reactions before starting experiments, one can easily determine an order of synthesis routes for experimental works. In the present study, the reaction profiles of the Curtius rearrangement with different substituents were calculated to generate an equation predicting experimental yields of this reaction. Reactions followed by the formation of isocyanates were also analyzed to consider the relationship between reaction times and experimental yields. A partial least squares (PLS) regression was used to correlate the experimental yields with the calculated activation energies, E a (calc), together with experimental conditions such as dielectric constants of solvents, reaction times, and reaction temperatures as explanatory variables. Although the PLS regression using all the data gave very poor results, we succeeded in making a model equation with R 2 = 0.887 using a modified data set. However, there is a conflict between the predictability and the interpretability on the reaction time. This discrepancy mainly comes from unnecessarily long reaction times in the experiments for azides with calculated E a values of less than 33 kcal mol -1 . To construct a good model equation for the experimental yields of the Curtius reaction, we have to use data sets obtained from within 90 min of the reaction for the PLS regression.

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Section: Resultsmentioning

confidence: 99%

\begin{matrix} Z_{italicobs} = I n (I n (C_{0} / C)) \\ ≅ a ln ε + β I n t + γ (- E_{a} (c a l c) / R T) + δ \\ = Z_{italiccalc} \end{matrix}

…”

Section: Methods Of Calculationsmentioning

confidence: 99%

Section: Methods Of Calculationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 94%

See 2 more Smart Citations

Predicting experimental yields as an index to rank synthesis routes II: application to the Curtius rearrangement

Yoshimura

Okano

Ishikawa

et al. 2011

J of Physical Organic Chem

Self Cite

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show abstract

“…Others now have acknowledged the importance of yield prediction as a valuable enabling tool for planning and selecting synthetic routes. [68,69] Hopefully, future chemists will be able to select a synthetic scheme for a desired product by employing retrosynthetic analysis in combination with predictive calculation of appropriate reaction conditions. An ideal objective would be to settle on the optimal pathway and yield before attempting any practical synthetic work and then to achieve the desired result experimentally, by green chemistry at the first attempt!…”

Section: Software For Predicting and Optimizing Yieldsmentioning

confidence: 99%

A Strategic, 'Green' Approach to Organic Chemistry with Microwave Assistance and Predictive Yield Optimization as Core, Enabling Technologies

Strauss¹

2009

Aust. J. Chem.

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Since 1988, we have pursued enabling technologies and methods as tools for 'green' synthetic chemistry. The developed technologies comprise hardware including catalytic membranes and continuous and batch microwave reactors that have established global markets, as well as interactive, predictive software for optimization of yields and translation of conditions. New methods include 'green' reactions such as a catalytic symmetrical etherification, Pd-catalyzed coupling processes and a multi-component cascade for aniline derivatives. Reactions and workup were facilitated through solvent-free conditions, aqueous media at high temperature and dimethylammonium dimethylcarbamate (dimcarb) as a 'distillable' protic ionic liquid, as well as by non-extractive techniques for product isolation. The technologies and methods were designed for use alone or in various combinations as desired. Consolidation of individual operations or processes into unit steps was achieved through multi-tasking: media, reactants, catalysts, and conditions were selected to serve several purposes at various stages of a reaction. The tools were used to establish a technology platform comprising structurally diverse oligomers, macrocycles, and rod-like molecules supplementary to those available through phenolformaldehyde chemistry. Dienone precursors were assembled from versatile building blocks containing complementary 'male' or 'female' fittings that were connected through inherently 'green' Claisen-Schmidt-type reactions. Isoaromatization afforded Horning-crowns, macrocyclic phenolic derivatives that were hybrids of calixarenes and crown ethers. Preliminary studies of organic substrates in salt water, with and without CO 2 , called into question proposals for disposal of anthropogenic CO 2 by deep-sea dispersal.

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Effect of hydrogen bonding on the intramolecular cycloaddition Diels–Alder reaction of triene-amide in an aqueous solution (case of a single molecule of water)

Benallou¹,

Abdallaoui²,

Garmes

2016

Tetrahedron

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Predicting experimental yields as an index to rank synthesis routes: application for Diels–Alder reactions

Cited by 6 publications

References 17 publications

Predicting experimental yields as an index to rank synthesis routes II: application to the Curtius rearrangement

Predicting experimental yields as an index to rank synthesis routes II: application to the Curtius rearrangement

A Strategic, 'Green' Approach to Organic Chemistry with Microwave Assistance and Predictive Yield Optimization as Core, Enabling Technologies

Effect of hydrogen bonding on the intramolecular cycloaddition Diels–Alder reaction of triene-amide in an aqueous solution (case of a single molecule of water)

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