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Filippo Silvestrini

Bio: Filippo Silvestrini is an academic researcher from University of Bologna. The author has contributed to research in topics: Michael reaction & Enantioselective synthesis. The author has an hindex of 1, co-authored 2 publications receiving 5 citations.

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TL;DR: In this paper, the structures, relative stabilities, and vibrational wavenumbers of the two most stable conformers of serine have been evaluated by means of state-of-the-art composite schemes based on coupled-cluster theory.
Abstract: The structures, relative stabilities, and vibrational wavenumbers of the two most stable conformers of serine, stabilized by the O-H···N, O-H···O═C and N-H···O-H intramolecular hydrogen bonds, have been evaluated by means of state-of-the-art composite schemes based on coupled-cluster (CC) theory. The so-called "cheap" composite approach (CCSD(T)/(CBS+CV)MP2) allowed determination of accurate equilibrium structures and harmonic vibrational wavenumbers, also pointing out significant corrections beyond the CCSD(T)/cc-pVTZ level. These accurate results stand as a reference for benchmarking selected hybrid and double-hybrid, dispersion-corrected DFT functionals. B2PLYP-D3 and DSDPBEP86 in conjunction with a triple-ζ basis set have been confirmed as effective methodologies for structural and spectroscopic studies of medium-sized flexible biomolecules, also showing intramolecular hydrogen bonding. These best performing double-hybrid functionals have been employed to simulate IR spectra by means of vibrational perturbation theory, also considering hybrid CC/DFT schemes. The best overall agreement with experiment, with mean absolute error of 8 cm-1, has been obtained by combining CCSD(T)/(CBS+CV)MP2 harmonic wavenumbers with B2PLYP-D3/maug-cc-pVTZ anharmonic corrections. Finally, a composite scheme entirely based on CCSD(T) calculations (CCSD(T)/CBS+CV) has been employed for energetics, further confirming that serine II is the most stable conformer, also when zero-point vibrational energy corrections are included.

5 citations


Cited by
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TL;DR: The oxa-Michael reaction (OMR) offers the most effective and straightforward route to the synthesis of a wide range of 5- and 6-membered oxygen-containing heterocycles including tetrahydropyrans, tetrahedrofurans, 1,4 dioxanes, isoxazolidines, oxoxazolines, γ-lactones, and related γbutenolides as discussed by the authors.
Abstract: The oxa-Michael reaction (OMR) offers the most effective and straightforward route to the synthesis of a wide range of 5- and 6-membered oxygen-containing heterocycles including tetrahydropyrans, tetrahydrofurans, 1,4 dioxanes, isoxazolidines, isoxazolines, γ-lactones and related γ-butenolides. These molecular frameworks are frequently featured in numerous biologically active substances. Moreover, the emergence of organocatalytic asymmetric OMR has empowered access to a variety of diverse oxygen-containing heterocycles in a highly enantio- and/or diastereoselective fashion. This review provides an updated account on the recent advances and applications of OMR in the synthesis 5- and 6-membered monocyclic oxo-heterocycles published in the literature since 2013 to date.

31 citations

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TL;DR: The ligand-free Co-catalyzed chemoselective reductive cyclization cascade of enone-tethered aldehydes with i-PrOH as the environmentally benign hydrogen surrogate is developed in this paper.

6 citations

Journal ArticleDOI
TL;DR: In this paper , a new computational setup rooted in quantum-chemical computations of increasing accuracy guided by machine learning tools is proposed to validate a new set of representative amino acids (glycine, alanine, serine, cysteine, threonine, aspartic acid and asparagine).
Abstract: The accurate characterization of prototypical bricks of life can strongly benefit from the integration of high resolution spectroscopy and quantum mechanical computations. We have selected a number of representative amino acids (glycine, alanine, serine, cysteine, threonine, aspartic acid and asparagine) to validate a new computational setup rooted in quantum-chemical computations of increasing accuracy guided by machine learning tools. Together with low-lying energy minima, the barriers ruling their interconversion are evaluated in order to unravel possible fast relaxation paths. Vibrational and thermal effects are also included in order to estimate relative free energies at the temperature of interest in the experiment. The spectroscopic parameters of all the most stable conformers predicted by this computational strategy, which do not have low-energy relaxation paths available, closely match those of the species detected in microwave experiments. Together with their intrinsic interest, these accurate results represent ideal benchmarks for more approximate methods.

6 citations

Journal ArticleDOI
TL;DR: In this paper , a model based on density functional theory is proposed to predict rotational constants with an accuracy of 0.3% or better, which can be used to characterize larger flexible building blocks.
Abstract: The interplay of high-resolution rotational spectroscopy and quantum-chemical computations plays an invaluable role in the investigation of biomolecule building blocks in the gas phase. However, quantum-chemical methods suffer from unfavorable scaling with the dimension of the system under consideration. While a complete characterization of flexible systems requires an elaborate multi-step strategy, in this work, we demonstrate that the accuracy obtained by quantum-chemical composite approaches in the prediction of rotational spectroscopy parameters can be approached by a model based on density functional theory. Glycine and serine are employed to demonstrate that, despite its limited cost, such a model is able to predict rotational constants with an accuracy of 0.3% or better, thus paving the way toward the accurate characterization of larger flexible building blocks of biomolecules.

5 citations