Enantiocontrolled solid-state photodimerizations via a chiral sulfonamidecinnamic acid

Wheeler, Kraig A.; Wiseman, Joshua D.; Grove, Rebecca C.

doi:10.1039/c0ce00516a

Cited by 17 publications

(11 citation statements)

References 33 publications

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“…As a result, each carbonyl has one aryl in cis and the other one in trans, each aryl has one carbonyl in cis and another one in trans, and the configuration of both molecules is 1,2- cis -2,3- trans -3,4- cis . The cyclobutane rings in these compounds are planar, as it is usually observed for other cyclobutanes containing this arrangement of groups, as are, for instance, the alpha-isomers of the truxillic acid and their related derivatives. ,− In all cases, the values of the internal parameters for bond distances (Å) and bond angles (deg) are as expected, and they do not show unusual deviations from values found in the literature for related structural arrangements. ,,,− …”

Section: Resultssupporting

confidence: 73%

“…The cyclobutane rings in these compounds are planar, as it is usually observed for other cyclobutanes containing this arrangement of groups, as are, for instance, the alpha-isomers of the truxillic acid and their related derivatives. 25,[30][31][32] In all cases, the values of the internal parameters for bond distances (Å) and bond angles (°) are as expected, and they do not show unusual deviations from values found in the literature for related structural arrangements. 15,19,25,[28][29][30][31][32][33] Revised manuscript.…”

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confidence: 83%

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Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

García‐Montero

Rodríguez

Juan

et al. 2017

ACS Sustainable Chem. Eng.

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The direct [2+2]-photocycloaddition of (Z)-2-phenyl-4-aryliden-5(4H)-oxazolones 1 to give 1,3-diaminotruxillic cyclobutane-derivatives 2 in very good yields (75-100%) is reported. The reaction takes place by irradiation of CH2Cl2 solutions of 1 with the blue light (465 nm) provided by LED lamps of low power (around 1 W) for 72 h. Four isomers of the 1,3diaminotruxillic cyclobutanes 2 were obtained, all of them fully characterized by a combination of NMR spectroscopy and X-ray diffraction analysis. The reaction shows a certain selectivity, since one of the isomers (the epsilon) is obtained preferentially, and works for electron-releasing and electron-withdrawing substituents at the arylidene ring. A novel setup is presented for the in-line monitoring of the continuous flow photo-assisted synthesis of the cyclobutane derivatives 2 by NMR spectroscopy, with the microreactor dramatically reducing reaction times to only 30 minutes with clear product distribution of up to four isomers. The mechanism of this [2+2]photocycloaddition has been calculated by DFT methods, explaining all experimental findings. The reaction takes place through a stepwise formation of two new CC bonds through a transient diradical singlet intermediate. The isomeric distribution of the final products is not due to equilibration processes, but instead reflects the kinetic preference during the rate limiting CC bond formation step.

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Section: Resultssupporting

confidence: 73%

supporting

confidence: 83%

Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

García‐Montero

Rodríguez

Juan

et al. 2017

ACS Sustainable Chem. Eng.

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“…The cyclobutane rings are not planar and exhibit dihedral angles of C1-C2-C101-C2 ( 3g ) = 18.1(3)°, C1-C9-C18-C26 ( 3h ) = 19.7(3)°, and C2-C10-C2-C10 ( 3m ) = 22.4(3)°, which are similar to those found in related cyclobutanes . In addition, the values for the remaining bond distances (Å) and angles (°) are in the usual range of values found in the literature for related structural arrangements. ,,,− …”

Section: Resultsmentioning

confidence: 57%

Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF₃

et al. 2021

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The irradiation of ( Z )-2-phenyl-4-aryliden-5(4 H )-thiazolones 2 with blue light (465 nm) in CH 2 Cl 2 solution promotes [2 + 2]-photocycloaddition of the exocyclic C=C bonds and the formation of the dispirocyclobutanes 3 . This reaction takes place with high stereoselectivity, given that the ε-isomer (1,3 head-to-tail syn coupling) is formed in more than 90% yield in most of the cases. However, irradiation of 5(4 H )-thiazolones 2 with blue light (456 nm) in dry MeOH in the presence of BF 3 ·OEt 2 leads to the monospirocyclobutanes 4 with full stereoselectivity, also affording the ε-isomer. A ring-opening reaction of only one of the thiazolone rings appears to have taken place in 4 upon methanolysis, leading to the corresponding ester and thioamide groups. The treatment of free 4-aryliden-5(4 H )-thiazolones 2 with a base in alcohol (NaOR/ROH) also produces a ring-opening reaction of the heterocycle by methanolysis, although, under these reaction conditions, further intramolecular S-attack at the exocyclic C(H)=C bond and cyclization is observed, forming the dihydrothiazoles 5 or 6 as mixtures of cis ( RS / SR )- and trans ( RR / SS )-isomers with high diastereomeric excess. trans -( RR/SS )-Dihydrothiazoles 6 can be isolated as pure diastereoisomers by column chromatography. Surprisingly, dihydrothiazoles 5 can also be obtained by the treatment of 4-aryliden-5(4 H )-thiazolones 2 with BF 3 ·OEt 2 in methanol in the absence of a base.

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“…Upon irradiation, the solid reacted to give the expected cyclobutane product stereo-and regio-specifically in quantitative yield. Similarly, Wheeler and coworkers employed chiral sulfonamidecinnamic acids 60 [96][97][98]. No matter the use of racemic (rac)-60a, quasiracemic [(R)-60a/(S)-60b], and homochiral (R)-60a reagents, the hydrogen bonding dimer persisted and afforded the cyclobutane photoproducts in single-crystal-to-single-crystal (SCSC) transformation (Fig.…”

Section: Self-complementary Reactantsmentioning

confidence: 94%

Hydrogen Bonding in Supramolecular Crystal Engineering

Wang

Zheng

2015

Lecture Notes in Chemistry

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This chapter emphases the important role of hydrogen bonding in crystal engineering for preparing fascinating architectures and engineering desired properties. The relatively high directionality and strength of hydrogen bonds make the prediction and control of molecular orientation in organic solids practical and reliable. Especially, strong hydrogen bonds like O-H···O, O-H···N, and N-H···O interactions are more useful. The introduction of supramolecular synthons and retrosynthesis theory has helped crystal chemists a lot in understanding and designing more complex structures. A large number of crystal structures reported in Cambridge Structure Database (CSD) provided a helpful tool for searching and analyzing specific interaction modes. Up to now, with the development of basic concepts and principles and the wide applications, the subject of crystal engineering has matured. Various intriguing structures and complicated entanglements have been constructed based on hydrogen bonds, such as nanocapsules, nanotubes, and n-Borromean arrayed topologies. The crystal engineering strategy has lent chemists the ability to control solid state reactions regio-and stereo-specifically and improve the physicochemical properties of drugs using pharmaceutical cocrystals. In addition, it will be seen that hydrogen bonding can also be used to prepare robust porous materials for gas adsorption and separation.

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Enantiocontrolled solid-state photodimerizations via a chiral sulfonamidecinnamic acid

Abstract: and Grive, Rebecca C., "Enantiocontrolled solid-state photodimerizations via a chiral sulfonamidecinnamic acid" (2011). Faculty Research and Creative Activity. 12.

Cited by 17 publications

References 33 publications

Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF₃

Hydrogen Bonding in Supramolecular Crystal Engineering

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Enantiocontrolled solid-state photodimerizations via a chiral sulfonamidecinnamic acid

Abstract: and Grive, Rebecca C., "Enantiocontrolled solid-state photodimerizations via a chiral sulfonamidecinnamic acid" (2011). Faculty Research and Creative Activity. 12.

Cited by 17 publications

References 33 publications

Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

Metal-Free [2 + 2]-Photocycloaddition of (Z)-4-Aryliden-5(4H)-Oxazolones as Straightforward Synthesis of 1,3-Diaminotruxillic Acid Precursors: Synthetic Scope and Mechanistic Studies

Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF3

Hydrogen Bonding in Supramolecular Crystal Engineering

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Reactivity of (Z)-4-Aryliden-5(4H)-thiazolones: [2 + 2]-Photocycloaddition, Ring-Opening Reactions, and Influence of the Lewis Acid BF₃